diff --git a/src/components/script/dom/bindings/codegen/CodegenRust.py b/src/components/script/dom/bindings/codegen/CodegenRust.py
index 8c3e650b01a..561466f00bf 100644
--- a/src/components/script/dom/bindings/codegen/CodegenRust.py
+++ b/src/components/script/dom/bindings/codegen/CodegenRust.py
@@ -1049,7 +1049,7 @@ for (uint32_t i = 0; i < length; ++i) {
             #    "if (!ConvertJSValueToString(cx, ${val}, ${valPtr}, %s, %s, %s)) {\n"
             #    "  return false;\n"
             #    "}" % (nullBehavior, undefinedBehavior, varName))
-            strval = "str(strval.unwrap())"
+            strval = "Some(strval.unwrap())"
             if isOptional:
                 strval = "Some(%s)" % strval
             conversionCode = (
@@ -1068,7 +1068,7 @@ for (uint32_t i = 0; i < length; ++i) {
             return handleDefault(
                 conversionCode,
                 ("static data: [u8, ..%s] = [ %s ];\n"
-                 "%s = str(str::from_utf8(data));" %
+                 "%s = Some(str::from_utf8(data));" %
                  (len(defaultValue.value) + 1,
                   ", ".join(["'" + char + "' as u8" for char in defaultValue.value] + ["0"]),
                   varName)))
@@ -2925,8 +2925,6 @@ class CGCallGenerator(CGThing):
         # Return values that go in outparams go here
         if resultOutParam:
             args.append(CGGeneric("result"))
-        if isFallible:
-            args.append(CGGeneric("&mut rv"))
 
         needsCx = (typeNeedsCx(returnType, True) or
                    any(typeNeedsCx(a.type) for (a, _) in arguments) or
@@ -2944,21 +2942,29 @@ class CGCallGenerator(CGThing):
         else: 
             call = CGWrapper(call, pre="(*%s)." % object)
         call = CGList([call, CGWrapper(args, pre="(", post=");")])
-        if result is not None:
-            if declareResult:
-                result = CGWrapper(result, pre="let mut result: ", post=";")
-                self.cgRoot.prepend(result)
-            if not resultOutParam:
-                call = CGWrapper(call, pre="result = ")
+
+        if isFallible:
+            self.cgRoot.prepend(CGWrapper(result if result is not None else CGGeneric("()"),
+                pre="let mut result_fallible: Result<", post=",Error>;"))
+
+        if result is not None and declareResult:
+            result = CGWrapper(result, pre="let mut result: ", post=";")
+            self.cgRoot.prepend(result)
+
+        if isFallible:
+            call = CGWrapper(call, pre="result_fallible = ")
+        elif result is not None and not resultOutParam:
+            call = CGWrapper(call, pre="result = ")
 
         call = CGWrapper(call)
         self.cgRoot.append(call)
 
         if isFallible:
-            self.cgRoot.prepend(CGGeneric("let mut rv: ErrorResult = Ok(());"))
-            self.cgRoot.append(CGGeneric("if (rv.is_err()) {"))
+            self.cgRoot.append(CGGeneric("if (result_fallible.is_err()) {"))
             self.cgRoot.append(CGIndenter(errorReport))
             self.cgRoot.append(CGGeneric("}"))
+            if result is not None and not resultOutParam:
+                self.cgRoot.append(CGGeneric("result = result_fallible.unwrap();"))
 
     def define(self):
         return self.cgRoot.define()
@@ -3190,7 +3196,7 @@ class CGAbstractBindingMethod(CGAbstractExternMethod):
                       "  return false as JSBool;\n"
                       "}\n"
                       "\n"
-                      "let this: *rust_box<%s>;" % self.descriptor.concreteType))
+                      "let this: *Box<%s>;" % self.descriptor.concreteType))
 
     def generate_code(self):
         assert(False) # Override me
@@ -3230,7 +3236,7 @@ class CGSpecializedMethod(CGAbstractExternMethod):
         self.method = method
         name = method.identifier.name
         args = [Argument('*JSContext', 'cx'), Argument('JSHandleObject', 'obj'),
-                Argument('*mut rust_box<%s>' % descriptor.concreteType, 'this'),
+                Argument('*mut Box<%s>' % descriptor.concreteType, 'this'),
                 Argument('libc::c_uint', 'argc'), Argument('*mut JSVal', 'vp')]
         CGAbstractExternMethod.__init__(self, descriptor, name, 'JSBool', args)
 
@@ -3247,7 +3253,7 @@ class CGSpecializedMethod(CGAbstractExternMethod):
                                       self.descriptor, self.method),
                          pre=extraPre +
                              "  let obj = (*obj.unnamed);\n" +
-                             "  let this = &mut (*this).payload;\n").define()
+                             "  let this = &mut (*this).data;\n").define()
 
 class CGGenericGetter(CGAbstractBindingMethod):
     """
@@ -3283,7 +3289,7 @@ class CGSpecializedGetter(CGAbstractExternMethod):
         name = 'get_' + attr.identifier.name
         args = [ Argument('*JSContext', 'cx'),
                  Argument('JSHandleObject', 'obj'),
-                 Argument('*mut rust_box<%s>' % descriptor.concreteType, 'this'),
+                 Argument('*mut Box<%s>' % descriptor.concreteType, 'this'),
                  Argument('*mut JSVal', 'vp') ]
         CGAbstractExternMethod.__init__(self, descriptor, name, "JSBool", args)
 
@@ -3309,7 +3315,7 @@ class CGSpecializedGetter(CGAbstractExternMethod):
                                                  self.descriptor, self.attr)),
                          pre=extraPre +
                              "  let obj = (*obj.unnamed);\n" +
-                             "  let this = &mut (*this).payload;\n").define()
+                             "  let this = &mut (*this).data;\n").define()
 
 class CGGenericSetter(CGAbstractBindingMethod):
     """
@@ -3350,7 +3356,7 @@ class CGSpecializedSetter(CGAbstractExternMethod):
         name = 'set_' + attr.identifier.name
         args = [ Argument('*JSContext', 'cx'),
                  Argument('JSHandleObject', 'obj'),
-                 Argument('*mut rust_box<%s>' % descriptor.concreteType, 'this'),
+                 Argument('*mut Box<%s>' % descriptor.concreteType, 'this'),
                  Argument('*mut JSVal', 'argv')]
         CGAbstractExternMethod.__init__(self, descriptor, name, "JSBool", args)
 
@@ -3367,7 +3373,7 @@ class CGSpecializedSetter(CGAbstractExternMethod):
                                                  self.descriptor, self.attr)),
                          pre=extraPre +
                              "  let obj = (*obj.unnamed);\n" +
-                             "  let this = &mut (*this).payload;\n").define()
+                             "  let this = &mut (*this).data;\n").define()
 
 def infallibleForMember(member, type, descriptorProvider):
     """
@@ -3642,8 +3648,8 @@ class CGProxyUnwrap(CGAbstractMethod):
     obj = js::UnwrapObject(obj);
   }*/
   //MOZ_ASSERT(IsProxy(obj));
-  let box: *rust_box<%s> = cast::transmute(RUST_JSVAL_TO_PRIVATE(GetProxyPrivate(obj)));
-  return ptr::to_unsafe_ptr(&(*box).payload);""" % (self.descriptor.concreteType)
+  let box: *Box<%s> = cast::transmute(RUST_JSVAL_TO_PRIVATE(GetProxyPrivate(obj)));
+  return ptr::to_unsafe_ptr(&(*box).data);""" % (self.descriptor.concreteType)
 
 class CGDOMJSProxyHandler_getOwnPropertyDescriptor(CGAbstractExternMethod):
     def __init__(self, descriptor):
@@ -3721,7 +3727,7 @@ class CGDOMJSProxyHandler_getOwnPropertyDescriptor(CGAbstractExternMethod):
                         "  if strval.is_err() {\n" +
                         "    return 0;\n" +
                         "  }\n" +
-                        "  let name = str(strval.unwrap());\n" +
+                        "  let name = Some(strval.unwrap());\n" +
                         "\n" +
                         "  let this: *%s = UnwrapProxy(proxy);\n" +
                         CGIndenter(CGProxyNamedGetter(self.descriptor, templateValues)).define() + "\n" +
@@ -3790,7 +3796,7 @@ class CGDOMJSProxyHandler_defineProperty(CGAbstractExternMethod):
                     "  if strval.is_err() {\n" +
                     "    return 0;\n" +
                     "  }\n" +
-                    "  let name = str(strval.unwrap());\n" +
+                    "  let name = Some(strval.unwrap());\n" +
                     "\n" +
                     "  let this: *%s = UnwrapProxy(proxy);\n" +
                     CGIndenter(CGProxyNamedSetter(self.descriptor)).define() + "\n" +
@@ -3806,7 +3812,7 @@ class CGDOMJSProxyHandler_defineProperty(CGAbstractExternMethod):
                     "  if strval.is_err() {\n" +
                     "    return 0;\n" +
                     "  }\n" +
-                    "  let name = str(strval.unwrap());\n" +
+                    "  let name = Some(strval.unwrap());\n" +
                     "  let this: %%s = UnwrapProxy(proxy);\n" +
                     CGIndenter(CGProxyNamedGetter(self.descriptor)).define() +
                     "  if (found) {\n"
@@ -3852,7 +3858,7 @@ class CGDOMJSProxyHandler_hasOwn(CGAbstractExternMethod):
                      "  if strval.is_err() {\n" +
                      "    return 0;\n" +
                      "  }\n" +
-                     "  let name = str(strval.unwrap());\n" +
+                     "  let name = Some(strval.unwrap());\n" +
                      "\n" +
                      "  let this: *%s = UnwrapProxy(proxy);\n" +
                      CGIndenter(CGProxyNamedGetter(self.descriptor)).define() + "\n" +
@@ -3997,7 +4003,7 @@ class CGAbstractClassHook(CGAbstractExternMethod):
 
     def definition_body_prologue(self):
         return """
-  let this: *%s = &(*unwrap::<*rust_box<%s>>(obj)).payload;
+  let this: *%s = &(*unwrap::<*Box<%s>>(obj)).data;
 """ % (self.descriptor.concreteType, self.descriptor.concreteType)
 
     def definition_body(self):
@@ -4686,6 +4692,7 @@ class CGBindingRoot(CGThing):
                           'std::vec',
                           'std::str',
                           'std::num',
+                          'std::unstable::raw::Box',
                          ], 
                          [],
                          curr)
diff --git a/src/components/script/dom/bindings/utils.rs b/src/components/script/dom/bindings/utils.rs
index e37f1d68153..6f931cc3290 100644
--- a/src/components/script/dom/bindings/utils.rs
+++ b/src/components/script/dom/bindings/utils.rs
@@ -14,7 +14,7 @@ use std::libc;
 use std::ptr;
 use std::ptr::{null, to_unsafe_ptr};
 use std::str;
-use std::unstable::intrinsics;
+use std::unstable::raw::Box;
 use js::glue::*;
 use js::glue::{DefineFunctionWithReserved, GetObjectJSClass, RUST_OBJECT_TO_JSVAL};
 use js::glue::{js_IsObjectProxyClass, js_IsFunctionProxyClass, IsProxyHandlerFamily};
@@ -83,48 +83,27 @@ extern fn InterfaceObjectToString(cx: *JSContext, _argc: c_uint, vp: *mut JSVal)
     }
 
     let name = jsval_to_str(cx, *v).unwrap();
-    let retval = str(~"function " + name + "() {\n    [native code]\n}");
+    let retval = Some(~"function " + name + "() {\n    [native code]\n}");
     *vp = domstring_to_jsval(cx, &retval);
     return 1;
   }
 }
 
-#[deriving(Clone)]
-pub enum DOMString {
-    str(~str),
-    null_string
-}
+pub type DOMString = Option<~str>;
 
-impl DOMString {
-    pub fn to_str(&self) -> ~str {
-        match *self {
-          str(ref s) => s.clone(),
-          null_string => ~""
-        }
-    }
-
-    pub fn get_ref<'a>(&'a self) -> &'a str {
-        match *self {
-            str(ref s) => s.as_slice(),
-            null_string => &'a "",
-        }
-    }
-
-    // XXX This is temporary until issue #875 is fixed.
-    pub fn unwrap(&self) -> ~str {
-        match self {
-          &str(ref s) => s.clone(),
-          &null_string => fail!("Cannot unwrap a null string.")
-        }
+pub fn null_str_as_empty(s: &DOMString) -> ~str {
+    // We don't use map_default because it would allocate ~"" even for Some.
+    match *s {
+        Some(ref s) => s.clone(),
+        None => ~""
     }
 }
 
-pub struct rust_box<T> {
-    rc: uint,
-    td: *intrinsics::TyDesc,
-    next: *(),
-    prev: *(),
-    payload: T
+pub fn null_str_as_empty_ref<'a>(s: &'a DOMString) -> &'a str {
+    match *s {
+        Some(ref s) => s.as_slice(),
+        None => &'a ""
+    }
 }
 
 fn is_dom_class(clasp: *JSClass) -> bool {
@@ -193,8 +172,8 @@ pub fn unwrap_value<T>(val: *JSVal, proto_id: PrototypeList::id::ID, proto_depth
     }
 }
 
-pub unsafe fn squirrel_away<T>(x: @mut T) -> *rust_box<T> {
-    let y: *rust_box<T> = cast::transmute(x);
+pub unsafe fn squirrel_away<T>(x: @mut T) -> *Box<T> {
+    let y: *Box<T> = cast::transmute(x);
     cast::forget(x);
     y
 }
@@ -223,10 +202,10 @@ pub fn jsval_to_str(cx: *JSContext, v: JSVal) -> Result<~str, ()> {
 #[fixed_stack_segment]
 pub unsafe fn domstring_to_jsval(cx: *JSContext, string: &DOMString) -> JSVal {
     match string {
-      &null_string => {
+      &None => {
         JSVAL_NULL
       }
-      &str(ref s) => {
+      &Some(ref s) => {
         do s.as_imm_buf |buf, len| {
             let cbuf = cast::transmute(buf);
             RUST_STRING_TO_JSVAL(JS_NewStringCopyN(cx, cbuf, len as libc::size_t))
@@ -536,7 +515,7 @@ pub fn initialize_global(global: *JSObject) {
     unsafe {
         //XXXjdm we should be storing the box pointer instead of the inner
         let box = squirrel_away(protoArray);
-        let inner = ptr::to_unsafe_ptr(&(*box).payload);
+        let inner = ptr::to_unsafe_ptr(&(*box).data);
         JS_SetReservedSlot(global,
                            DOM_PROTOTYPE_SLOT,
                            RUST_PRIVATE_TO_JSVAL(inner as *libc::c_void));
@@ -773,7 +752,9 @@ pub enum Error {
     InvalidCharacter,
 }
 
-pub type ErrorResult = Result<(), Error>;
+pub type Fallible<T> = Result<T, Error>;
+
+pub type ErrorResult = Fallible<()>;
 
 pub struct EnumEntry {
     value: &'static str,
diff --git a/src/components/script/dom/characterdata.rs b/src/components/script/dom/characterdata.rs
index 04c9ceead32..283f0a74f4e 100644
--- a/src/components/script/dom/characterdata.rs
+++ b/src/components/script/dom/characterdata.rs
@@ -4,7 +4,7 @@
 
 //! DOM bindings for `CharacterData`.
 
-use dom::bindings::utils::{DOMString, str, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult, Fallible};
 use dom::bindings::utils::{BindingObject, CacheableWrapper, WrapperCache};
 use dom::node::{Node, NodeTypeId, ScriptView};
 use js::jsapi::{JSObject, JSContext};
@@ -23,34 +23,36 @@ impl CharacterData {
     }
     
     pub fn Data(&self) -> DOMString {
-        str(self.data.clone())
+        Some(self.data.clone())
     }
 
-    pub fn SetData(&mut self, arg: &DOMString, _rv: &mut ErrorResult) {
-        self.data = arg.unwrap();
+    pub fn SetData(&mut self, arg: &DOMString) -> ErrorResult {
+        self.data = arg.get_ref().clone();
+        Ok(())
     }
 
     pub fn Length(&self) -> u32 {
         self.data.len() as u32
     }
 
-    pub fn SubstringData(&self, offset: u32, count: u32, _rv: &mut ErrorResult) -> DOMString {
-        str(self.data.slice(offset as uint, count as uint).to_str())
+    pub fn SubstringData(&self, offset: u32, count: u32) -> Fallible<DOMString> {
+        Ok(Some(self.data.slice(offset as uint, count as uint).to_str()))
     }
 
-    pub fn AppendData(&mut self, arg: &DOMString, _rv: &mut ErrorResult) {
-        self.data.push_str(arg.unwrap());
+    pub fn AppendData(&mut self, arg: &DOMString) -> ErrorResult {
+        self.data.push_str(arg.get_ref().clone());
+        Ok(())
     }
 
-    pub fn InsertData(&mut self, _offset: u32, _arg: &DOMString, _rv: &mut ErrorResult) {
+    pub fn InsertData(&mut self, _offset: u32, _arg: &DOMString) -> ErrorResult {
         fail!("CharacterData::InsertData() is unimplemented")
     }
 
-    pub fn DeleteData(&mut self, _offset: u32, _count: u32, _rv: &mut ErrorResult) {
+    pub fn DeleteData(&mut self, _offset: u32, _count: u32) -> ErrorResult {
         fail!("CharacterData::DeleteData() is unimplemented")
     }
 
-    pub fn ReplaceData(&mut self, _offset: u32, _count: u32, _arg: &DOMString, _rv: &mut ErrorResult) {
+    pub fn ReplaceData(&mut self, _offset: u32, _count: u32, _arg: &DOMString) -> ErrorResult {
         fail!("CharacterData::ReplaceData() is unimplemented")
     }
 }
diff --git a/src/components/script/dom/comment.rs b/src/components/script/dom/comment.rs
index 126178ca5d0..8cda0a033b4 100644
--- a/src/components/script/dom/comment.rs
+++ b/src/components/script/dom/comment.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, str, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, Fallible, null_str_as_empty};
 use dom::characterdata::CharacterData;
 use dom::node::{AbstractNode, ScriptView, CommentNodeTypeId, Node};
 use dom::window::Window;
@@ -20,14 +20,11 @@ impl Comment {
         }
     }
 
-    pub fn Constructor(owner: @mut Window, data: &DOMString, _rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
-        let s = match *data {
-            str(ref s) => s.clone(),
-            null_string => ~""
-        };
+    pub fn Constructor(owner: @mut Window, data: &DOMString) -> Fallible<AbstractNode<ScriptView>> {
+        let s = null_str_as_empty(data);
         unsafe {
             let compartment = (*owner.page).js_info.get_ref().js_compartment;
-            Node::as_abstract_node(compartment.cx.ptr, @Comment::new(s))
+            Ok(Node::as_abstract_node(compartment.cx.ptr, @Comment::new(s)))
         }
     }
 }
diff --git a/src/components/script/dom/document.rs b/src/components/script/dom/document.rs
index 137ba6cf1e9..5ad111c0515 100644
--- a/src/components/script/dom/document.rs
+++ b/src/components/script/dom/document.rs
@@ -3,9 +3,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::DocumentBinding;
-use dom::bindings::utils::{DOMString, WrapperCache, ErrorResult, null_string, str};
-use dom::bindings::utils::{BindingObject, CacheableWrapper, rust_box, DerivedWrapper};
-use dom::bindings::utils::{is_valid_element_name, InvalidCharacter, Traceable};
+use dom::bindings::utils::{DOMString, WrapperCache, ErrorResult, Fallible};
+use dom::bindings::utils::{BindingObject, CacheableWrapper, DerivedWrapper};
+use dom::bindings::utils::{is_valid_element_name, InvalidCharacter, Traceable, null_str_as_empty};
 use dom::element::{Element};
 use dom::element::{HTMLHtmlElementTypeId, HTMLHeadElementTypeId, HTMLTitleElementTypeId};
 use dom::event::Event;
@@ -29,6 +29,7 @@ use std::ptr;
 use std::str::eq_slice;
 use std::libc;
 use std::ascii::StrAsciiExt;
+use std::unstable::raw::Box;
 
 pub trait WrappableDocument {
     fn init_wrapper(@mut self, cx: *JSContext);
@@ -48,13 +49,13 @@ impl AbstractDocument {
     }
 
     unsafe fn transmute<T, R>(&self, f: &fn(&T) -> R) -> R {
-        let box: *rust_box<T> = cast::transmute(self.document);
-        f(&(*box).payload)
+        let box: *Box<T> = cast::transmute(self.document);
+        f(&(*box).data)
     }
 
     unsafe fn transmute_mut<T, R>(&self, f: &fn(&mut T) -> R) -> R {
-        let box: *mut rust_box<T> = cast::transmute(self.document);
-        f(&mut (*box).payload)
+        let box: *mut Box<T> = cast::transmute(self.document);
+        f(&mut (*box).data)
     }
 
     pub fn with_base<R>(&self, callback: &fn(&Document) -> R) -> R {
@@ -103,14 +104,14 @@ impl Document {
         }
     }
 
-    pub fn Constructor(owner: @mut Window, _rv: &mut ErrorResult) -> AbstractDocument {
+    pub fn Constructor(owner: @mut Window) -> Fallible<AbstractDocument> {
         let root = @HTMLHtmlElement {
             parent: HTMLElement::new(HTMLHtmlElementTypeId, ~"html")
         };
 
         let cx = owner.page.js_info.get_ref().js_compartment.cx.ptr;
         let root = unsafe { Node::as_abstract_node(cx, root) };
-        AbstractDocument::as_abstract(cx, @mut Document::new(root, None, XML))
+        Ok(AbstractDocument::as_abstract(cx, @mut Document::new(root, None, XML)))
     }
 }
 
@@ -187,23 +188,23 @@ impl BindingObject for Document {
 
 impl Document {
     pub fn URL(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn DocumentURI(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn CompatMode(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn CharacterSet(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn ContentType(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn GetDocumentElement(&self) -> Option<AbstractNode<ScriptView>> {
@@ -224,7 +225,7 @@ impl Document {
     }
 
     pub fn GetElementsByTagName(&self, tag: &DOMString) -> @mut HTMLCollection {
-        self.createHTMLCollection(|elem| eq_slice(elem.tag_name, tag.to_str()))
+        self.createHTMLCollection(|elem| eq_slice(elem.tag_name, null_str_as_empty(tag)))
     }
 
     pub fn GetElementsByTagNameNS(&self, _ns: &DOMString, _tag: &DOMString) -> @mut HTMLCollection {
@@ -241,45 +242,43 @@ impl Document {
         None
     }
 
-    pub fn CreateElement(&self, local_name: &DOMString, rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+    pub fn CreateElement(&self, local_name: &DOMString) -> Fallible<AbstractNode<ScriptView>> {
         let cx = self.get_cx();
-        let local_name = local_name.to_str();
+        let local_name = null_str_as_empty(local_name);
         if !is_valid_element_name(local_name) {
-            *rv = Err(InvalidCharacter);
-            // FIXME #909: what to return here?
-            fail!("invalid character");
+            return Err(InvalidCharacter);
         }
         let local_name = local_name.to_ascii_lower();
-        build_element_from_tag(cx, local_name)
+        Ok(build_element_from_tag(cx, local_name))
     }
 
-    pub fn CreateElementNS(&self, _namespace: &DOMString, _qualified_name: &DOMString, _rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+    pub fn CreateElementNS(&self, _namespace: &DOMString, _qualified_name: &DOMString) -> Fallible<AbstractNode<ScriptView>> {
         fail!("stub")
     }
 
     pub fn CreateTextNode(&self, data: &DOMString) -> AbstractNode<ScriptView> {
         let cx = self.get_cx();
-        unsafe { Node::as_abstract_node(cx, @Text::new(data.to_str())) }
+        unsafe { Node::as_abstract_node(cx, @Text::new(null_str_as_empty(data))) }
     }
 
-    pub fn CreateEvent(&self, _interface: &DOMString, _rv: &mut ErrorResult) -> @mut Event {
+    pub fn CreateEvent(&self, _interface: &DOMString) -> Fallible<@mut Event> {
         fail!("stub")
     }
 
     pub fn GetInputEncoding(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn Referrer(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn LastModified(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn ReadyState(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn Title(&self) -> DOMString {
@@ -297,7 +296,7 @@ impl Document {
                         if child.is_text() {
                             do child.with_imm_text() |text| {
                                 let s = text.parent.Data();
-                                title = title + s.to_str();
+                                title = title + null_str_as_empty(&s);
                             }
                         }
                     }
@@ -308,10 +307,10 @@ impl Document {
         let v: ~[&str] = title.word_iter().collect();
         title = v.connect(" ");
         title = title.trim().to_owned();
-        str(title)
+        Some(title)
     }
 
-    pub fn SetTitle(&self, title: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetTitle(&self, title: &DOMString) -> ErrorResult {
         match self.doctype {
             SVG => {
                 fail!("no SVG document yet")
@@ -348,10 +347,11 @@ impl Document {
                 };
             }
         }
+        Ok(())
     }
 
     pub fn Dir(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetDir(&self, _dir: &DOMString) {
@@ -365,8 +365,8 @@ impl Document {
         None
     }
 
-    pub fn HasFocus(&self, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn HasFocus(&self) -> Fallible<bool> {
+        Ok(false)
     }
 
     pub fn GetCurrentScript(&self) -> Option<AbstractNode<ScriptView>> {
@@ -380,8 +380,8 @@ impl Document {
         false
     }
 
-    pub fn GetMozFullScreenElement(&self, _rv: &mut ErrorResult) -> Option<AbstractNode<ScriptView>> {
-        None
+    pub fn GetMozFullScreenElement(&self) -> Fallible<Option<AbstractNode<ScriptView>>> {
+        Ok(None)
     }
 
     pub fn GetMozPointerLockElement(&self) -> Option<AbstractNode<ScriptView>> {
@@ -408,18 +408,18 @@ impl Document {
     }
 
     pub fn GetSelectedStyleSheetSet(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetSelectedStyleSheetSet(&self, _sheet: &DOMString) {
     }
 
     pub fn GetLastStyleSheetSet(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn GetPreferredStyleSheetSet(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn EnableStyleSheetsForSet(&self, _name: &DOMString) {
@@ -429,13 +429,13 @@ impl Document {
         None
     }
 
-    pub fn QuerySelector(&self, _selectors: &DOMString, _rv: &mut ErrorResult) -> Option<AbstractNode<ScriptView>> {
-        None
+    pub fn QuerySelector(&self, _selectors: &DOMString) -> Fallible<Option<AbstractNode<ScriptView>>> {
+        Ok(None)
     }
 
     pub fn GetElementsByName(&self, name: &DOMString) -> @mut HTMLCollection {
         self.createHTMLCollection(|elem|
-            elem.get_attr("name").is_some() && eq_slice(elem.get_attr("name").unwrap(), name.to_str()))
+            elem.get_attr("name").is_some() && eq_slice(elem.get_attr("name").unwrap(), null_str_as_empty(name)))
     }
 
     pub fn createHTMLCollection(&self, callback: &fn(elem: &Element) -> bool) -> @mut HTMLCollection {
diff --git a/src/components/script/dom/documenttype.rs b/src/components/script/dom/documenttype.rs
index 3ac1d1f0db0..1a4fa918550 100644
--- a/src/components/script/dom/documenttype.rs
+++ b/src/components/script/dom/documenttype.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, str, null_string};
+use dom::bindings::utils::DOMString;
 use dom::node::{ScriptView, Node, DoctypeNodeTypeId};
 
 /// The `DOCTYPE` tag.
@@ -31,20 +31,14 @@ impl DocumentType<ScriptView> {
     }
 
     pub fn Name(&self) -> DOMString {
-        str(self.name.clone())
+        Some(self.name.clone())
     }
 
     pub fn PublicId(&self) -> DOMString {
-        match self.public_id {
-            Some(ref s) => str(s.clone()),
-            None => null_string
-        }
+        self.public_id.clone()
     }
 
     pub fn SystemId(&self) -> DOMString {
-        match self.system_id {
-            Some(ref s) => str(s.clone()),
-            None => null_string
-        }
+        self.system_id.clone()
     }
 }
diff --git a/src/components/script/dom/domparser.rs b/src/components/script/dom/domparser.rs
index df8d275a07e..c28dc723218 100644
--- a/src/components/script/dom/domparser.rs
+++ b/src/components/script/dom/domparser.rs
@@ -4,7 +4,7 @@
 
 use dom::bindings::codegen::DOMParserBinding;
 use dom::bindings::codegen::DOMParserBinding::SupportedTypeValues::{Text_html, Text_xml};
-use dom::bindings::utils::{DOMString, ErrorResult, WrapperCache, CacheableWrapper};
+use dom::bindings::utils::{DOMString, Fallible, WrapperCache, CacheableWrapper};
 use dom::document::{AbstractDocument, Document, XML};
 use dom::element::HTMLHtmlElementTypeId;
 use dom::htmldocument::HTMLDocument;
@@ -33,15 +33,14 @@ impl DOMParser {
         parser
     }
 
-    pub fn Constructor(owner: @mut Window, _rv: &mut ErrorResult) -> @mut DOMParser {
-        DOMParser::new(owner)
+    pub fn Constructor(owner: @mut Window) -> Fallible<@mut DOMParser> {
+        Ok(DOMParser::new(owner))
     }
 
     pub fn ParseFromString(&self,
                            _s: &DOMString,
-                           ty: DOMParserBinding::SupportedType,
-                           _rv: &mut ErrorResult)
-                           -> AbstractDocument {
+                           ty: DOMParserBinding::SupportedType)
+                           -> Fallible<AbstractDocument> {
         unsafe {
             let root = @HTMLHtmlElement {
                 parent: HTMLElement::new(HTMLHtmlElementTypeId, ~"html")
@@ -52,10 +51,10 @@ impl DOMParser {
 
             match ty {
                 Text_html => {
-                    HTMLDocument::new(root, None)
+                    Ok(HTMLDocument::new(root, None))
                 }
                 Text_xml => {
-                    AbstractDocument::as_abstract(cx, @mut Document::new(root, None, XML))
+                    Ok(AbstractDocument::as_abstract(cx, @mut Document::new(root, None, XML)))
                 }
                 _ => {
                     fail!("unsupported document type")
diff --git a/src/components/script/dom/element.rs b/src/components/script/dom/element.rs
index 50bd41358e2..520e57ec0d1 100644
--- a/src/components/script/dom/element.rs
+++ b/src/components/script/dom/element.rs
@@ -4,8 +4,8 @@
 
 //! Element nodes.
 
-use dom::bindings::utils::{null_string, str};
-use dom::bindings::utils::{BindingObject, CacheableWrapper, DOMString, ErrorResult, WrapperCache};
+use dom::bindings::utils::{BindingObject, CacheableWrapper, DOMString, ErrorResult, Fallible, WrapperCache};
+use dom::bindings::utils::{null_str_as_empty, null_str_as_empty_ref};
 use dom::htmlcollection::HTMLCollection;
 use dom::clientrect::ClientRect;
 use dom::clientrectlist::ClientRectList;
@@ -143,8 +143,8 @@ impl<'self> Element {
                     abstract_self: AbstractNode<ScriptView>,
                     raw_name: &DOMString,
                     raw_value: &DOMString) {
-        let name = raw_name.to_str();
-        let value_cell = Cell::new(raw_value.to_str());
+        let name = null_str_as_empty(raw_name);
+        let value_cell = Cell::new(null_str_as_empty(raw_value));
         let mut found = false;
         for attr in self.attrs.mut_iter() {
             if eq_slice(attr.name, name) {
@@ -161,7 +161,7 @@ impl<'self> Element {
             self.style_attribute = Some(
                 Stylesheet::from_attribute(
                     FromStr::from_str("http://www.example.com/").unwrap(),
-                    raw_value.get_ref()));
+                    null_str_as_empty_ref(raw_value)));
         }
 
         //XXXjdm We really need something like a vtable so we can call AfterSetAttr.
@@ -198,44 +198,42 @@ impl<'self> Element {
 
 impl Element {
     pub fn TagName(&self) -> DOMString {
-        str(self.tag_name.to_owned().to_ascii_upper())
+        Some(self.tag_name.to_owned().to_ascii_upper())
     }
 
     pub fn Id(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetId(&self, _id: &DOMString) {
     }
 
     pub fn GetAttribute(&self, name: &DOMString) -> DOMString {
-        match self.get_attr(name.get_ref()) {
-            Some(val) => str(val.to_owned()),
-            None => null_string
-        }
+        self.get_attr(null_str_as_empty_ref(name)).map(|s| s.to_owned())
     }
 
     pub fn GetAttributeNS(&self, _namespace: &DOMString, _localname: &DOMString) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetAttribute(&mut self,
                         abstract_self: AbstractNode<ScriptView>,
                         name: &DOMString,
-                        value: &DOMString,
-                        _rv: &mut ErrorResult) {
+                        value: &DOMString) -> ErrorResult {
         self.set_attr(abstract_self, name, value);
+        Ok(())
     }
 
-    pub fn SetAttributeNS(&self, _namespace: &DOMString, _localname: &DOMString, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAttributeNS(&self, _namespace: &DOMString, _localname: &DOMString, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn RemoveAttribute(&self, _name: &DOMString, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn RemoveAttribute(&self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn RemoveAttributeNS(&self, _namespace: &DOMString, _localname: &DOMString, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn RemoveAttributeNS(&self, _namespace: &DOMString, _localname: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn HasAttribute(&self, _name: &DOMString) -> bool {
@@ -251,9 +249,9 @@ impl Element {
         HTMLCollection::new(~[], cx, scope)
     }
 
-    pub fn GetElementsByTagNameNS(&self, _namespace: &DOMString, _localname: &DOMString, _rv: &mut ErrorResult) -> @mut HTMLCollection {
+    pub fn GetElementsByTagNameNS(&self, _namespace: &DOMString, _localname: &DOMString) -> Fallible<@mut HTMLCollection> {
         let (scope, cx) = self.get_scope_and_cx();
-        HTMLCollection::new(~[], cx, scope)
+        Ok(HTMLCollection::new(~[], cx, scope))
     }
 
     pub fn GetElementsByClassName(&self, _names: &DOMString) -> @mut HTMLCollection {
@@ -261,8 +259,8 @@ impl Element {
         HTMLCollection::new(~[], cx, scope)
     }
 
-    pub fn MozMatchesSelector(&self, _selector: &DOMString, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn MozMatchesSelector(&self, _selector: &DOMString) -> Fallible<bool> {
+        Ok(false)
     }
 
     pub fn SetCapture(&self, _retargetToElement: bool) {
@@ -391,25 +389,28 @@ impl Element {
         0
     }
 
-    pub fn GetInnerHTML(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetInnerHTML(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn SetInnerHTML(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetInnerHTML(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn GetOuterHTML(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetOuterHTML(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn SetOuterHTML(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetOuterHTML(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn InsertAdjacentHTML(&mut self, _position: &DOMString, _text: &DOMString, _rv: &mut ErrorResult) {
+    pub fn InsertAdjacentHTML(&mut self, _position: &DOMString, _text: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn QuerySelector(&self, _selectors: &DOMString, _rv: &mut ErrorResult) -> Option<AbstractNode<ScriptView>> {
-        None
+    pub fn QuerySelector(&self, _selectors: &DOMString) -> Fallible<Option<AbstractNode<ScriptView>>> {
+        Ok(None)
     }
 }
 
diff --git a/src/components/script/dom/event.rs b/src/components/script/dom/event.rs
index b8e17706c07..745bd323581 100644
--- a/src/components/script/dom/event.rs
+++ b/src/components/script/dom/event.rs
@@ -6,7 +6,7 @@ use dom::eventtarget::EventTarget;
 use dom::window::Window;
 use dom::bindings::codegen::EventBinding;
 use dom::bindings::utils::{CacheableWrapper, BindingObject, DerivedWrapper};
-use dom::bindings::utils::{DOMString, ErrorResult, WrapperCache};
+use dom::bindings::utils::{DOMString, ErrorResult, Fallible, WrapperCache};
 
 use geom::point::Point2D;
 use js::glue::RUST_OBJECT_TO_JSVAL;
@@ -95,11 +95,11 @@ impl Event {
     pub fn InitEvent(&mut self,
                      type_: &DOMString,
                      bubbles: bool,
-                     cancelable: bool,
-                     _rv: &mut ErrorResult) {
+                     cancelable: bool) -> ErrorResult {
         self.type_ = (*type_).clone();
         self.cancelable = cancelable;
         self.bubbles = bubbles;
+        Ok(())
     }
 
     pub fn IsTrusted(&self) -> bool {
@@ -108,9 +108,8 @@ impl Event {
 
     pub fn Constructor(_global: @mut Window,
                    type_: &DOMString,
-                   _init: &EventBinding::EventInit,
-                   _rv: &mut ErrorResult) -> @mut Event {
-        @mut Event::new(type_)
+                   _init: &EventBinding::EventInit) -> Fallible<@mut Event> {
+        Ok(@mut Event::new(type_))
     }
 }
 
diff --git a/src/components/script/dom/formdata.rs b/src/components/script/dom/formdata.rs
index 4bac8e18966..008f524091e 100644
--- a/src/components/script/dom/formdata.rs
+++ b/src/components/script/dom/formdata.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::utils::{CacheableWrapper, BindingObject, DerivedWrapper};
-use dom::bindings::utils::{WrapperCache, DOMString, str};
+use dom::bindings::utils::{WrapperCache, DOMString, null_str_as_empty};
 use dom::bindings::codegen::FormDataBinding;
 use dom::blob::Blob;
 use script_task::{page_from_context};
@@ -39,13 +39,13 @@ impl FormData {
     pub fn Append(&mut self, name: &DOMString, value: @mut Blob, filename: Option<DOMString>) {
         let blob = BlobData {
             blob: value,
-            name: filename.unwrap_or_default(str(~"default"))
+            name: filename.unwrap_or_default(Some(~"default"))
         };
-        self.data.insert(name.to_str(), blob);
+        self.data.insert(null_str_as_empty(name), blob);
     }
 
     pub fn Append_(&mut self, name: &DOMString, value: &DOMString) {
-        self.data.insert(name.to_str(), StringData((*value).clone()));
+        self.data.insert(null_str_as_empty(name), StringData((*value).clone()));
     }
 }
 
diff --git a/src/components/script/dom/htmlanchorelement.rs b/src/components/script/dom/htmlanchorelement.rs
index 4c8160b0c1b..d8bac8176ee 100644
--- a/src/components/script/dom/htmlanchorelement.rs
+++ b/src/components/script/dom/htmlanchorelement.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::htmlelement::HTMLElement;
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 
 pub struct HTMLAnchorElement {
     parent: HTMLElement
@@ -11,93 +11,106 @@ pub struct HTMLAnchorElement {
 
 impl HTMLAnchorElement {
     pub fn Href(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHref(&mut self, _href: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHref(&mut self, _href: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Target(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetTarget(&self, _target: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetTarget(&self, _target: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Download(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDownload(&self, _download: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDownload(&self, _download: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Ping(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetPing(&self, _ping: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetPing(&self, _ping: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Rel(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetRel(&self, _rel: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetRel(&self, _rel: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Hreflang(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHreflang(&self, _href_lang: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHreflang(&self, _href_lang: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Text(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetText(&mut self, _text: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetText(&mut self, _text: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Coords(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCoords(&mut self, _coords: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCoords(&mut self, _coords: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Charset(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCharset(&mut self, _charset: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCharset(&mut self, _charset: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Rev(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetRev(&mut self, _rev: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetRev(&mut self, _rev: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Shape(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetShape(&mut self, _shape: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetShape(&mut self, _shape: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlappletelement.rs b/src/components/script/dom/htmlappletelement.rs
index 8c8ee5e6cf1..187c6635440 100644
--- a/src/components/script/dom/htmlappletelement.rs
+++ b/src/components/script/dom/htmlappletelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLAppletElement {
@@ -11,79 +11,90 @@ pub struct HTMLAppletElement {
 
 impl HTMLAppletElement {
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Alt(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlt(&self, _alt: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlt(&self, _alt: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Archive(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetArchive(&self, _archive: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetArchive(&self, _archive: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Code(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCode(&self, _code: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCode(&self, _code: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CodeBase(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCodeBase(&self, _code_base: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCodeBase(&self, _code_base: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHeight(&self, _height: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHeight(&self, _height: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Hspace(&self) -> u32 {
         0
     }
 
-    pub fn SetHspace(&mut self, _hspace: u32, _rv: &mut ErrorResult) {
+    pub fn SetHspace(&mut self, _hspace: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Object(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetObject(&mut self, _object: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetObject(&mut self, _object: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Vspace(&self) -> u32 {
         0
     }
 
-    pub fn SetVspace(&mut self, _vspace: u32, _rv: &mut ErrorResult) {
+    pub fn SetVspace(&mut self, _vspace: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&mut self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlareaelement.rs b/src/components/script/dom/htmlareaelement.rs
index 8dd146d4b71..df5fe4fce81 100644
--- a/src/components/script/dom/htmlareaelement.rs
+++ b/src/components/script/dom/htmlareaelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLAreaElement {
@@ -11,58 +11,66 @@ pub struct HTMLAreaElement {
 
 impl HTMLAreaElement {
     pub fn Alt(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlt(&self, _alt: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlt(&self, _alt: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Coords(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCoords(&self, _coords: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCoords(&self, _coords: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Shape(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetShape(&self, _shape: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetShape(&self, _shape: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Href(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHref(&self, _href: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHref(&self, _href: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Target(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetTarget(&self, _target: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetTarget(&self, _target: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Download(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDownload(&self, _download: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDownload(&self, _download: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Ping(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetPing(&self, _ping: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetPing(&self, _ping: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn NoHref(&self) -> bool {
         false
     }
 
-    pub fn SetNoHref(&mut self, _no_href: bool, _rv: &mut ErrorResult) {
+    pub fn SetNoHref(&mut self, _no_href: bool) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlbaseelement.rs b/src/components/script/dom/htmlbaseelement.rs
index 6df670c9bdb..78168507533 100644
--- a/src/components/script/dom/htmlbaseelement.rs
+++ b/src/components/script/dom/htmlbaseelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLBaseElement {
@@ -11,16 +11,18 @@ pub struct HTMLBaseElement {
 
 impl HTMLBaseElement {
     pub fn Href(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHref(&self, _href: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHref(&self, _href: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Target(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetTarget(&self, _target: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetTarget(&self, _target: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlbodyelement.rs b/src/components/script/dom/htmlbodyelement.rs
index f6781d3bbc9..85918884793 100644
--- a/src/components/script/dom/htmlbodyelement.rs
+++ b/src/components/script/dom/htmlbodyelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLBodyElement {
@@ -11,44 +11,50 @@ pub struct HTMLBodyElement {
 
 impl HTMLBodyElement {
     pub fn Text(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetText(&mut self, _text: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetText(&mut self, _text: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Link(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetLink(&self, _link: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetLink(&self, _link: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn VLink(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetVLink(&self, _v_link: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetVLink(&self, _v_link: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ALink(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetALink(&self, _a_link: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetALink(&self, _a_link: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn BgColor(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBgColor(&self, _bg_color: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBgColor(&self, _bg_color: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Background(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBackground(&self, _background: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBackground(&self, _background: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlbrelement.rs b/src/components/script/dom/htmlbrelement.rs
index e89bedff047..164d8d13176 100644
--- a/src/components/script/dom/htmlbrelement.rs
+++ b/src/components/script/dom/htmlbrelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLBRElement {
@@ -11,9 +11,10 @@ pub struct HTMLBRElement {
 
 impl HTMLBRElement {
     pub fn Clear(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetClear(&mut self, _text: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetClear(&mut self, _text: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlbuttonelement.rs b/src/components/script/dom/htmlbuttonelement.rs
index fa831c67fd3..dbc84a6e4a3 100644
--- a/src/components/script/dom/htmlbuttonelement.rs
+++ b/src/components/script/dom/htmlbuttonelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 use dom::node::{AbstractNode, ScriptView};
 use dom::validitystate::ValidityState;
@@ -16,14 +16,16 @@ impl HTMLButtonElement {
         false
     }
 
-    pub fn SetAutofocus(&mut self, _autofocus: bool, _rv: &mut ErrorResult) {
+    pub fn SetAutofocus(&mut self, _autofocus: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Disabled(&self) -> bool {
         false
     }
 
-    pub fn SetDisabled(&mut self, _disabled: bool, _rv: &mut ErrorResult) {
+    pub fn SetDisabled(&mut self, _disabled: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetForm(&self) -> Option<AbstractNode<ScriptView>> {
@@ -31,59 +33,67 @@ impl HTMLButtonElement {
     }
 
     pub fn FormAction(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormAction(&mut self, _formaction: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormAction(&mut self, _formaction: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormEnctype(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormEnctype(&mut self, _formenctype: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormEnctype(&mut self, _formenctype: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormMethod(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormMethod(&mut self, _formmethod: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormMethod(&mut self, _formmethod: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormNoValidate(&self) -> bool {
         false
     }
 
-    pub fn SetFormNoValidate(&mut self, _novalidate: bool, _rv: &mut ErrorResult) {
+    pub fn SetFormNoValidate(&mut self, _novalidate: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormTarget(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormTarget(&mut self, _formtarget: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormTarget(&mut self, _formtarget: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
     
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValue(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn WillValidate(&self) -> bool {
@@ -101,10 +111,11 @@ impl HTMLButtonElement {
     }
 
     pub fn ValidationMessage(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValidationMessage(&mut self, _message: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValidationMessage(&mut self, _message: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CheckValidity(&self) -> bool {
@@ -113,4 +124,4 @@ impl HTMLButtonElement {
 
     pub fn SetCustomValidity(&mut self, _error: &DOMString) {
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlcanvaselement.rs b/src/components/script/dom/htmlcanvaselement.rs
index fd2caad56ce..1afcbc667ec 100644
--- a/src/components/script/dom/htmlcanvaselement.rs
+++ b/src/components/script/dom/htmlcanvaselement.rs
@@ -14,13 +14,15 @@ impl HTMLCanvasElement {
         0
     }
 
-    pub fn SetWidth(&mut self, _width: u32, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> u32 {
         0
     }
 
-    pub fn SetHeight(&mut self, _height: u32, _rv: &mut ErrorResult) {
+    pub fn SetHeight(&mut self, _height: u32) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlcollection.rs b/src/components/script/dom/htmlcollection.rs
index db668d70e64..a16b2090355 100644
--- a/src/components/script/dom/htmlcollection.rs
+++ b/src/components/script/dom/htmlcollection.rs
@@ -4,7 +4,7 @@
 
 use dom::bindings::codegen::HTMLCollectionBinding;
 use dom::bindings::utils::{CacheableWrapper, BindingObject, WrapperCache};
-use dom::bindings::utils::{DOMString, ErrorResult};
+use dom::bindings::utils::{DOMString, Fallible};
 use dom::node::{AbstractNode, ScriptView};
 use script_task::page_from_context;
 
@@ -44,9 +44,8 @@ impl HTMLCollection {
         }
     }
 
-    pub fn NamedItem(&self, _cx: *JSContext, _name: &DOMString, rv: &mut ErrorResult) -> *JSObject {
-        *rv = Ok(());
-        ptr::null()
+    pub fn NamedItem(&self, _cx: *JSContext, _name: &DOMString) -> Fallible<*JSObject> {
+        Ok(ptr::null())
     }
 
     pub fn IndexedGetter(&self, index: u32, found: &mut bool) -> Option<AbstractNode<ScriptView>> {
@@ -54,8 +53,8 @@ impl HTMLCollection {
         self.Item(index)
     }
 
-    pub fn NamedGetter(&self, _cx: *JSContext, _name: &DOMString, _found: &mut bool, _rv: &mut ErrorResult) -> *JSObject {
-        ptr::null()
+    pub fn NamedGetter(&self, _cx: *JSContext, _name: &DOMString, _found: &mut bool) -> Fallible<*JSObject> {
+        Ok(ptr::null())
     }
 }
 
diff --git a/src/components/script/dom/htmldataelement.rs b/src/components/script/dom/htmldataelement.rs
index dd2ed31a6da..7b175e1853f 100644
--- a/src/components/script/dom/htmldataelement.rs
+++ b/src/components/script/dom/htmldataelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLDataElement {
@@ -11,9 +11,10 @@ pub struct HTMLDataElement {
 
 impl HTMLDataElement {
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValue(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmldirectoryelement.rs b/src/components/script/dom/htmldirectoryelement.rs
index 2c6899745fb..2d5eb5fd48d 100644
--- a/src/components/script/dom/htmldirectoryelement.rs
+++ b/src/components/script/dom/htmldirectoryelement.rs
@@ -14,6 +14,7 @@ impl HTMLDirectoryElement {
         false
     }
 
-    pub fn SetCompact(&mut self, _compact: bool, _rv: &mut ErrorResult) {
+    pub fn SetCompact(&mut self, _compact: bool) -> ErrorResult {
+        Ok(())
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmldivelement.rs b/src/components/script/dom/htmldivelement.rs
index b46281234e7..d626873251e 100644
--- a/src/components/script/dom/htmldivelement.rs
+++ b/src/components/script/dom/htmldivelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLDivElement {
@@ -11,9 +11,10 @@ pub struct HTMLDivElement {
 
 impl HTMLDivElement {
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmldlistelement.rs b/src/components/script/dom/htmldlistelement.rs
index ff6908746ec..6ce58ba1195 100644
--- a/src/components/script/dom/htmldlistelement.rs
+++ b/src/components/script/dom/htmldlistelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLDListElement {
@@ -14,13 +14,15 @@ impl HTMLDListElement {
         false
     }
 
-    pub fn SetCompact(&mut self, _compact: bool, _rv: &mut ErrorResult) {
+    pub fn SetCompact(&mut self, _compact: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmldocument.rs b/src/components/script/dom/htmldocument.rs
index abdd9646cea..855231ea637 100644
--- a/src/components/script/dom/htmldocument.rs
+++ b/src/components/script/dom/htmldocument.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::HTMLDocumentBinding;
-use dom::bindings::utils::{DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{DOMString, ErrorResult, Fallible};
 use dom::bindings::utils::{CacheableWrapper, BindingObject, WrapperCache};
 use dom::document::{AbstractDocument, Document, WrappableDocument, HTML};
 use dom::element::HTMLHeadElementTypeId;
@@ -49,22 +49,24 @@ impl WrappableDocument for HTMLDocument {
 }
 
 impl HTMLDocument {
-    pub fn NamedGetter(&self, _cx: *JSContext, _name: &DOMString, _found: &mut bool, _rv: &mut ErrorResult) -> *JSObject {
-        ptr::null()
+    pub fn NamedGetter(&self, _cx: *JSContext, _name: &DOMString, _found: &mut bool) -> Fallible<*JSObject> {
+        Ok(ptr::null())
     }
 
-    pub fn GetDomain(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetDomain(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn SetDomain(&self, _domain: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDomain(&self, _domain: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn GetCookie(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetCookie(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn SetCookie(&self, _cookie: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCookie(&self, _cookie: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetHead(&self) -> Option<AbstractNode<ScriptView>> {
@@ -104,70 +106,72 @@ impl HTMLDocument {
         self.parent.createHTMLCollection(|elem| eq_slice(elem.tag_name, "script"))
     }
 
-    pub fn Close(&self, _rv: &mut ErrorResult) {
+    pub fn Close(&self) -> ErrorResult {
+        Ok(())
     }
 
     pub fn DesignMode(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDesignMode(&self, _mode: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDesignMode(&self, _mode: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn ExecCommand(&self, _command_id: &DOMString, _show_ui: bool, _value: &DOMString, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn ExecCommand(&self, _command_id: &DOMString, _show_ui: bool, _value: &DOMString) -> Fallible<bool> {
+        Ok(false)
     }
 
-    pub fn QueryCommandEnabled(&self, _command_id: &DOMString, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn QueryCommandEnabled(&self, _command_id: &DOMString) -> Fallible<bool> {
+        Ok(false)
     }
 
-    pub fn QueryCommandIndeterm(&self, _command_id: &DOMString, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn QueryCommandIndeterm(&self, _command_id: &DOMString) -> Fallible<bool> {
+        Ok(false)
     }
 
-    pub fn QueryCommandState(&self, _command_id: &DOMString, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn QueryCommandState(&self, _command_id: &DOMString) -> Fallible<bool> {
+        Ok(false)
     }
 
     pub fn QueryCommandSupported(&self, _command_id: &DOMString) -> bool {
         false
     }
 
-    pub fn QueryCommandValue(&self, _command_id: &DOMString, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn QueryCommandValue(&self, _command_id: &DOMString) -> Fallible<DOMString> {
+        Ok(None)
     }
 
     pub fn FgColor(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetFgColor(&self, _color: &DOMString) {
     }
 
     pub fn LinkColor(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetLinkColor(&self, _color: &DOMString) {
     }
 
     pub fn VlinkColor(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetVlinkColor(&self, _color: &DOMString) {
     }
 
     pub fn AlinkColor(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetAlinkColor(&self, _color: &DOMString) {
     }
 
     pub fn BgColor(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetBgColor(&self, _color: &DOMString) {
@@ -186,8 +190,8 @@ impl HTMLDocument {
     pub fn Clear(&self) {
     }
 
-    pub fn GetAll(&self, _cx: *JSContext, _rv: &mut ErrorResult) -> *libc::c_void {
-        ptr::null()
+    pub fn GetAll(&self, _cx: *JSContext) -> Fallible<*libc::c_void> {
+        Ok(ptr::null())
     }
 }
 
diff --git a/src/components/script/dom/htmlelement.rs b/src/components/script/dom/htmlelement.rs
index a28c87afad5..7dcb43aad5e 100644
--- a/src/components/script/dom/htmlelement.rs
+++ b/src/components/script/dom/htmlelement.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::HTMLElementBinding;
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult, Fallible};
 use dom::bindings::utils::{CacheableWrapper, BindingObject, WrapperCache};
 use dom::element::{Element, ElementTypeId};
 use dom::node::{AbstractNode, ScriptView};
@@ -24,38 +24,41 @@ impl HTMLElement {
 
 impl HTMLElement {
     pub fn Title(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetTitle(&mut self, _title: &DOMString) {
     }
 
     pub fn Lang(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetLang(&mut self, _lang: &DOMString) {
     }
 
     pub fn Dir(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDir(&mut self, _dir: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDir(&mut self, _dir: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn GetItemValue(&self, _cx: *JSContext, _rv: &mut ErrorResult) -> JSVal {
-        JSVAL_NULL
+    pub fn GetItemValue(&self, _cx: *JSContext) -> Fallible<JSVal> {
+        Ok(JSVAL_NULL)
     }
 
-    pub fn SetItemValue(&mut self, _cx: *JSContext, _val: JSVal, _rv: &mut ErrorResult) {
+    pub fn SetItemValue(&mut self, _cx: *JSContext, _val: JSVal) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Hidden(&self) -> bool {
         false
     }
 
-    pub fn SetHidden(&mut self, _hidden: bool, _rv: &mut ErrorResult) {
+    pub fn SetHidden(&mut self, _hidden: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Click(&self) {
@@ -65,38 +68,44 @@ impl HTMLElement {
         0
     }
 
-    pub fn SetTabIndex(&mut self, _index: i32, _rv: &mut ErrorResult) {
+    pub fn SetTabIndex(&mut self, _index: i32) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn Focus(&self, _rv: &mut ErrorResult) {
+    pub fn Focus(&self) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn Blur(&self, _rv: &mut ErrorResult) {
+    pub fn Blur(&self) -> ErrorResult {
+        Ok(())
     }
 
     pub fn AccessKey(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAccessKey(&self, _key: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAccessKey(&self, _key: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn AccessKeyLabel(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn Draggable(&self) -> bool {
         false
     }
 
-    pub fn SetDraggable(&mut self, _draggable: bool, _rv: &mut ErrorResult) {
+    pub fn SetDraggable(&mut self, _draggable: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ContentEditable(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetContentEditable(&mut self, _val: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetContentEditable(&mut self, _val: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn IsContentEditable(&self) -> bool {
@@ -107,11 +116,12 @@ impl HTMLElement {
         false
     }
 
-    pub fn SetSpellcheck(&self, _val: bool, _rv: &mut ErrorResult) {
+    pub fn SetSpellcheck(&self, _val: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ClassName(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetClassName(&self, _class: &DOMString) {
diff --git a/src/components/script/dom/htmlembedelement.rs b/src/components/script/dom/htmlembedelement.rs
index 2d86fa6f2e7..0ae3b926eb8 100644
--- a/src/components/script/dom/htmlembedelement.rs
+++ b/src/components/script/dom/htmlembedelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::document::AbstractDocument;
 use dom::htmlelement::HTMLElement;
 
@@ -12,45 +12,51 @@ pub struct HTMLEmbedElement {
 
 impl HTMLEmbedElement {
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&mut self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHeight(&mut self, _height: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHeight(&mut self, _height: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetSVGDocument(&self) -> Option<AbstractDocument> {
diff --git a/src/components/script/dom/htmlfieldsetelement.rs b/src/components/script/dom/htmlfieldsetelement.rs
index 67518289d86..7a8e19b01ef 100644
--- a/src/components/script/dom/htmlfieldsetelement.rs
+++ b/src/components/script/dom/htmlfieldsetelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult, CacheableWrapper};
+use dom::bindings::utils::{DOMString, ErrorResult, CacheableWrapper};
 use dom::htmlcollection::HTMLCollection;
 use dom::htmlelement::HTMLElement;
 use dom::node::{AbstractNode, ScriptView};
@@ -19,7 +19,8 @@ impl HTMLFieldSetElement {
         false
     }
 
-    pub fn SetDisabled(&mut self, _disabled: bool, _rv: &mut ErrorResult) {
+    pub fn SetDisabled(&mut self, _disabled: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetForm(&self) -> Option<AbstractNode<ScriptView>> {
@@ -27,14 +28,15 @@ impl HTMLFieldSetElement {
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
     fn get_scope_and_cx(&self) -> (*JSObject, *JSContext) {
@@ -60,7 +62,7 @@ impl HTMLFieldSetElement {
     }
 
     pub fn ValidationMessage(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn CheckValidity(&self) -> bool {
@@ -69,4 +71,4 @@ impl HTMLFieldSetElement {
 
     pub fn SetCustomValidity(&mut self, _error: &DOMString) {
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlfontelement.rs b/src/components/script/dom/htmlfontelement.rs
index eff3d85ae3b..d0152bc7f25 100644
--- a/src/components/script/dom/htmlfontelement.rs
+++ b/src/components/script/dom/htmlfontelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLFontElement {
@@ -11,23 +11,26 @@ pub struct HTMLFontElement {
 
 impl HTMLFontElement {
     pub fn Color(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetColor(&mut self, _color: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetColor(&mut self, _color: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Face(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFace(&mut self, _face: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFace(&mut self, _face: &DOMString) -> ErrorResult {
+        Ok(())
     }
     
     pub fn Size(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSize(&mut self, _size: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSize(&mut self, _size: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlformelement.rs b/src/components/script/dom/htmlformelement.rs
index f83d544425c..5cfa3e68bfd 100644
--- a/src/components/script/dom/htmlformelement.rs
+++ b/src/components/script/dom/htmlformelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{CacheableWrapper, DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{CacheableWrapper, DOMString, ErrorResult};
 use dom::element::HTMLFormElementTypeId;
 use dom::htmlcollection::HTMLCollection;
 use dom::htmlelement::HTMLElement;
@@ -25,66 +25,75 @@ impl HTMLFormElement {
     }
 
     pub fn AcceptCharset(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAcceptCharset(&mut self, _accept_charset: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAcceptCharset(&mut self, _accept_charset: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Action(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAction(&mut self, _action: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAction(&mut self, _action: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Autocomplete(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAutocomplete(&mut self, _autocomplete: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAutocomplete(&mut self, _autocomplete: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Enctype(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetEnctype(&mut self, _enctype: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetEnctype(&mut self, _enctype: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Encoding(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetEncoding(&mut self, _encoding: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetEncoding(&mut self, _encoding: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Method(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMethod(&mut self, _method: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMethod(&mut self, _method: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn NoValidate(&self) -> bool {
         false
     }
 
-    pub fn SetNoValidate(&mut self, _no_validate: bool, _rv: &mut ErrorResult) {
+    pub fn SetNoValidate(&mut self, _no_validate: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Target(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetTarget(&mut self, _target: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetTarget(&mut self, _target: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Elements(&self) -> @mut HTMLCollection {
@@ -96,7 +105,8 @@ impl HTMLFormElement {
         0
     }
     
-    pub fn Submit(&self, _rv: &mut ErrorResult) {
+    pub fn Submit(&self) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Reset(&self) {
diff --git a/src/components/script/dom/htmlframeelement.rs b/src/components/script/dom/htmlframeelement.rs
index 64ce1537363..3dd275797be 100644
--- a/src/components/script/dom/htmlframeelement.rs
+++ b/src/components/script/dom/htmlframeelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::document::AbstractDocument;
 use dom::htmlelement::HTMLElement;
 use dom::windowproxy::WindowProxy;
@@ -13,45 +13,51 @@ pub struct HTMLFrameElement {
 
 impl HTMLFrameElement {
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Scrolling(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetScrolling(&mut self, _scrolling: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetScrolling(&mut self, _scrolling: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FrameBorder(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFrameBorder(&mut self, _frameborder: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFrameBorder(&mut self, _frameborder: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn LongDesc(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetLongDesc(&mut self, _longdesc: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetLongDesc(&mut self, _longdesc: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn NoResize(&self) -> bool {
         false
     }
 
-    pub fn SetNoResize(&mut self, _no_resize: bool, _rv: &mut ErrorResult) {
+    pub fn SetNoResize(&mut self, _no_resize: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetContentDocument(&self) -> Option<AbstractDocument> {
@@ -63,16 +69,18 @@ impl HTMLFrameElement {
     }
 
     pub fn MarginHeight(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMarginHeight(&mut self, _height: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMarginHeight(&mut self, _height: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn MarginWidth(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMarginWidth(&mut self, _height: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMarginWidth(&mut self, _height: &DOMString) -> ErrorResult {
+        Ok(())
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlframesetelement.rs b/src/components/script/dom/htmlframesetelement.rs
index ff483633083..0660380757b 100644
--- a/src/components/script/dom/htmlframesetelement.rs
+++ b/src/components/script/dom/htmlframesetelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLFrameSetElement {
@@ -11,16 +11,18 @@ pub struct HTMLFrameSetElement {
 
 impl HTMLFrameSetElement {
     pub fn Cols(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCols(&mut self, _cols: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCols(&mut self, _cols: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Rows(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetRows(&mut self, _rows: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetRows(&mut self, _rows: &DOMString) -> ErrorResult {
+        Ok(())
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlheadingelement.rs b/src/components/script/dom/htmlheadingelement.rs
index d94bd06dab4..33231737bb7 100644
--- a/src/components/script/dom/htmlheadingelement.rs
+++ b/src/components/script/dom/htmlheadingelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string};
+use dom::bindings::utils::DOMString;
 use dom::htmlelement::HTMLElement;
 
 pub enum HeadingLevel {
@@ -21,7 +21,7 @@ pub struct HTMLHeadingElement {
 
 impl HTMLHeadingElement {
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetAlign(&mut self, _align: &DOMString) {
diff --git a/src/components/script/dom/htmlhrelement.rs b/src/components/script/dom/htmlhrelement.rs
index d1a3bb0348e..08ce278d2e7 100644
--- a/src/components/script/dom/htmlhrelement.rs
+++ b/src/components/script/dom/htmlhrelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLHRElement {
@@ -11,37 +11,42 @@ pub struct HTMLHRElement {
 
 impl HTMLHRElement {
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Color(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetColor(&mut self, _color: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetColor(&mut self, _color: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn NoShade(&self) -> bool {
         false
     }
 
-    pub fn SetNoShade(&self, _no_shade: bool, _rv: &mut ErrorResult) {
+    pub fn SetNoShade(&self, _no_shade: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Size(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSize(&mut self, _size: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSize(&mut self, _size: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&mut self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlhtmlelement.rs b/src/components/script/dom/htmlhtmlelement.rs
index 7aa36abb90c..7e292c9c557 100644
--- a/src/components/script/dom/htmlhtmlelement.rs
+++ b/src/components/script/dom/htmlhtmlelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLHtmlElement {
@@ -11,9 +11,10 @@ pub struct HTMLHtmlElement {
 
 impl HTMLHtmlElement {
     pub fn Version(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetVersion(&mut self, _version: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetVersion(&mut self, _version: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmliframeelement.rs b/src/components/script/dom/htmliframeelement.rs
index 27a6dee1601..3ddab8af1ea 100644
--- a/src/components/script/dom/htmliframeelement.rs
+++ b/src/components/script/dom/htmliframeelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult, str};
+use dom::bindings::utils::{DOMString, ErrorResult, null_str_as_empty};
 use dom::document::AbstractDocument;
 use dom::htmlelement::HTMLElement;
 use dom::node::{AbstractNode, ScriptView};
@@ -60,40 +60,42 @@ impl HTMLIFrameElement {
 
 impl HTMLIFrameElement {
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Srcdoc(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrcdoc(&mut self, _srcdoc: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrcdoc(&mut self, _srcdoc: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Sandbox(&self, _abstract_self: AbstractNode<ScriptView>) -> DOMString {
-        self.parent.parent.GetAttribute(&str(~"sandbox"))
+        self.parent.parent.GetAttribute(&Some(~"sandbox"))
     }
 
     pub fn SetSandbox(&mut self, abstract_self: AbstractNode<ScriptView>, sandbox: &DOMString) {
-        let mut rv = Ok(());
-        self.parent.parent.SetAttribute(abstract_self, &str(~"sandbox"), sandbox, &mut rv);
+        self.parent.parent.SetAttribute(abstract_self, &Some(~"sandbox"), sandbox);
     }
 
     pub fn AfterSetAttr(&mut self, name: &DOMString, value: &DOMString) {
-        let name = name.to_str();
+        let name = null_str_as_empty(name);
         if "sandbox" == name {
             let mut modes = AllowNothing as u8;
-            let words = value.to_str();
+            let words = null_str_as_empty(value);
             for word in words.split_iter(' ') {
                 modes |= match word.to_ascii_lower().as_slice() {
                     "allow-same-origin" => AllowSameOrigin,
@@ -113,21 +115,24 @@ impl HTMLIFrameElement {
         false
     }
 
-    pub fn SetAllowFullscreen(&mut self, _allow: bool, _rv: &mut ErrorResult) {
+    pub fn SetAllowFullscreen(&mut self, _allow: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&mut self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHeight(&mut self, _height: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHeight(&mut self, _height: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetContentDocument(&self) -> Option<AbstractDocument> {
@@ -139,45 +144,51 @@ impl HTMLIFrameElement {
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Scrolling(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetScrolling(&mut self, _scrolling: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetScrolling(&mut self, _scrolling: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FrameBorder(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFrameBorder(&mut self, _frameborder: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFrameBorder(&mut self, _frameborder: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn LongDesc(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetLongDesc(&mut self, _longdesc: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetLongDesc(&mut self, _longdesc: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn MarginHeight(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMarginHeight(&mut self, _marginheight: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMarginHeight(&mut self, _marginheight: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn MarginWidth(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMarginWidth(&mut self, _marginwidth: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMarginWidth(&mut self, _marginwidth: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetSVGDocument(&self) -> Option<AbstractDocument> {
diff --git a/src/components/script/dom/htmlimageelement.rs b/src/components/script/dom/htmlimageelement.rs
index 1ab87a62368..661d14ef891 100644
--- a/src/components/script/dom/htmlimageelement.rs
+++ b/src/components/script/dom/htmlimageelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, str, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult, null_str_as_empty};
 use dom::htmlelement::HTMLElement;
 use dom::node::{ScriptView, AbstractNode};
 use extra::url::Url;
@@ -40,7 +40,7 @@ impl HTMLImageElement {
     }
 
     pub fn AfterSetAttr(&mut self, name: &DOMString, _value: &DOMString) {
-        let name = name.to_str();
+        let name = null_str_as_empty(name);
         if "src" == name {
             let doc = self.parent.parent.parent.owner_doc;
             for doc in doc.iter() {
@@ -55,45 +55,49 @@ impl HTMLImageElement {
     }
 
     pub fn Alt(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlt(&mut self, _alt: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlt(&mut self, _alt: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Src(&self, _abstract_self: AbstractNode<ScriptView>) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetSrc(&mut self,
                   abstract_self: AbstractNode<ScriptView>,
-                  src: &DOMString,
-                  _rv: &mut ErrorResult) {
+                  src: &DOMString) -> ErrorResult {
         let node = &mut self.parent.parent;
         node.set_attr(abstract_self,
-                      &str(~"src"),
-                      &str(src.to_str()));
+                      &Some(~"src"),
+                      &Some(null_str_as_empty(src)));
+        Ok(())
     }
 
     pub fn CrossOrigin(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn UseMap(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetUseMap(&mut self, _use_map: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetUseMap(&mut self, _use_map: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn IsMap(&self) -> bool {
         false
     }
 
-    pub fn SetIsMap(&self, _is_map: bool, _rv: &mut ErrorResult) {
+    pub fn SetIsMap(&self, _is_map: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self, abstract_self: AbstractNode<ScriptView>) -> u32 {
@@ -125,12 +129,12 @@ impl HTMLImageElement {
 
     pub fn SetWidth(&mut self,
                     abstract_self: AbstractNode<ScriptView>,
-                    width: u32,
-                    _rv: &mut ErrorResult) {
+                    width: u32) -> ErrorResult {
         let node = &mut self.parent.parent;
         node.set_attr(abstract_self,
-                      &str(~"width"),
-                      &str(width.to_str()));
+                      &Some(~"width"),
+                      &Some(width.to_str()));
+        Ok(())
     }
 
     pub fn Height(&self, abstract_self: AbstractNode<ScriptView>) -> u32 {
@@ -162,12 +166,12 @@ impl HTMLImageElement {
 
     pub fn SetHeight(&mut self,
                      abstract_self: AbstractNode<ScriptView>,
-                     height: u32,
-                     _rv: &mut ErrorResult) {
+                     height: u32) -> ErrorResult {
         let node = &mut self.parent.parent;
         node.set_attr(abstract_self,
-                      &str(~"height"),
-                      &str(height.to_str()));
+                      &Some(~"height"),
+                      &Some(height.to_str()));
+        Ok(())
     }
 
     pub fn NaturalWidth(&self) -> u32 {
@@ -183,44 +187,50 @@ impl HTMLImageElement {
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Hspace(&self) -> u32 {
         0
     }
 
-    pub fn SetHspace(&mut self, _hspace: u32, _rv: &mut ErrorResult) {
+    pub fn SetHspace(&mut self, _hspace: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Vspace(&self) -> u32 {
         0
     }
 
-    pub fn SetVspace(&mut self, _vspace: u32, _rv: &mut ErrorResult) {
+    pub fn SetVspace(&mut self, _vspace: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn LongDesc(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetLongDesc(&mut self, _longdesc: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetLongDesc(&mut self, _longdesc: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Border(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBorder(&mut self, _border: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBorder(&mut self, _border: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlinputelement.rs b/src/components/script/dom/htmlinputelement.rs
index 8dbcc1826e9..abf4b0b470a 100644
--- a/src/components/script/dom/htmlinputelement.rs
+++ b/src/components/script/dom/htmlinputelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult, Fallible};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLInputElement {
@@ -11,38 +11,43 @@ pub struct HTMLInputElement {
 
 impl HTMLInputElement {
     pub fn Accept(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAccept(&mut self, _accept: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAccept(&mut self, _accept: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Alt(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlt(&mut self, _alt: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlt(&mut self, _alt: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Autocomplete(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAutocomplete(&mut self, _autocomple: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAutocomplete(&mut self, _autocomple: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Autofocus(&self) -> bool {
         false
     }
 
-    pub fn SetAutofocus(&mut self, _autofocus: bool, _rv: &mut ErrorResult) {
+    pub fn SetAutofocus(&mut self, _autofocus: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn DefaultChecked(&self) -> bool {
         false
     }
 
-    pub fn SetDefaultChecked(&mut self, _default_checked: bool, _rv: &mut ErrorResult) {
+    pub fn SetDefaultChecked(&mut self, _default_checked: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Checked(&self) -> bool {
@@ -56,49 +61,56 @@ impl HTMLInputElement {
         false
     }
 
-    pub fn SetDisabled(&mut self, _disabled: bool, _rv: &mut ErrorResult) {
+    pub fn SetDisabled(&mut self, _disabled: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormAction(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormAction(&mut self, _form_action: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormAction(&mut self, _form_action: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormEnctype(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormEnctype(&mut self, _form_enctype: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormEnctype(&mut self, _form_enctype: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormMethod(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormMethod(&mut self, _form_method: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormMethod(&mut self, _form_method: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormNoValidate(&self) -> bool {
         false
     }
 
-    pub fn SetFormNoValidate(&mut self, _form_no_validate: bool, _rv: &mut ErrorResult) {
+    pub fn SetFormNoValidate(&mut self, _form_no_validate: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn FormTarget(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFormTarget(&mut self, _form_target: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFormTarget(&mut self, _form_target: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> u32 {
         0
     }
 
-    pub fn SetHeight(&mut self, _height: u32, _rv: &mut ErrorResult) {
+    pub fn SetHeight(&mut self, _height: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Indeterminate(&self) -> bool {
@@ -109,115 +121,131 @@ impl HTMLInputElement {
     }
 
     pub fn InputMode(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetInputMode(&mut self, _input_mode: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetInputMode(&mut self, _input_mode: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Max(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMax(&mut self, _max: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMax(&mut self, _max: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn MaxLength(&self) -> i32 {
         0
     }
 
-    pub fn SetMaxLength(&mut self, _max_length: i32, _rv: &mut ErrorResult) {
+    pub fn SetMaxLength(&mut self, _max_length: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Min(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMin(&mut self, _min: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMin(&mut self, _min: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Multiple(&self) -> bool {
         false
     }
 
-    pub fn SetMultiple(&mut self, _multiple: bool, _rv: &mut ErrorResult) {
+    pub fn SetMultiple(&mut self, _multiple: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Pattern(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetPattern(&mut self, _pattern: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetPattern(&mut self, _pattern: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Placeholder(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetPlaceholder(&mut self, _placeholder: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetPlaceholder(&mut self, _placeholder: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ReadOnly(&self) -> bool {
         false
     }
 
-    pub fn SetReadOnly(&mut self, _read_only: bool, _rv: &mut ErrorResult) {
+    pub fn SetReadOnly(&mut self, _read_only: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Required(&self) -> bool {
         false
     }
 
-    pub fn SetRequired(&mut self, _required: bool, _rv: &mut ErrorResult) {
+    pub fn SetRequired(&mut self, _required: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Size(&self) -> u32 {
         0
     }
 
-    pub fn SetSize(&mut self, _size: u32, _rv: &mut ErrorResult) {
+    pub fn SetSize(&mut self, _size: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Step(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetStep(&mut self, _step: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetStep(&mut self, _step: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn DefaultValue(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDefaultValue(&mut self, _default_value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDefaultValue(&mut self, _default_value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValue(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> u32 {
@@ -234,8 +262,8 @@ impl HTMLInputElement {
     pub fn SetWillValidate(&self, _will_validate: bool) {
     }
 
-    pub fn GetValidationMessage(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetValidationMessage(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
     pub fn CheckValidity(&self) -> bool {
@@ -248,38 +276,43 @@ impl HTMLInputElement {
     pub fn Select(&self) {
     }
 
-    pub fn GetSelectionStart(&self, _rv: &mut ErrorResult) -> i32 {
-        0
+    pub fn GetSelectionStart(&self) -> Fallible<i32> {
+        Ok(0)
     }
 
-    pub fn SetSelectionStart(&mut self, _selection_start: i32, _rv: &mut ErrorResult) {
+    pub fn SetSelectionStart(&mut self, _selection_start: i32) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn GetSelectionEnd(&self, _rv: &mut ErrorResult) -> i32 {
-        0
+    pub fn GetSelectionEnd(&self) -> Fallible<i32> {
+        Ok(0)
     }
 
-    pub fn SetSelectionEnd(&mut self, _selection_end: i32, _rv: &mut ErrorResult) {
+    pub fn SetSelectionEnd(&mut self, _selection_end: i32) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn GetSelectionDirection(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetSelectionDirection(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn SetSelectionDirection(&mut self, _selection_direction: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSelectionDirection(&mut self, _selection_direction: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn UseMap(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetUseMap(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetUseMap(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmllabelelement.rs b/src/components/script/dom/htmllabelelement.rs
index 1df3924cff2..17d2c98b5a8 100644
--- a/src/components/script/dom/htmllabelelement.rs
+++ b/src/components/script/dom/htmllabelelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string};
+use dom::bindings::utils::DOMString;
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLLabelElement {
@@ -11,7 +11,7 @@ pub struct HTMLLabelElement {
 
 impl HTMLLabelElement {
     pub fn HtmlFor(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetHtmlFor(&mut self, _html_for: &DOMString) {
diff --git a/src/components/script/dom/htmllegendelement.rs b/src/components/script/dom/htmllegendelement.rs
index f7f67e87265..96327c3e8cd 100644
--- a/src/components/script/dom/htmllegendelement.rs
+++ b/src/components/script/dom/htmllegendelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLLegendElement {
@@ -11,9 +11,10 @@ pub struct HTMLLegendElement {
 
 impl HTMLLegendElement {
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmllielement.rs b/src/components/script/dom/htmllielement.rs
index facc81d9a37..1e0966ab4b4 100644
--- a/src/components/script/dom/htmllielement.rs
+++ b/src/components/script/dom/htmllielement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLLIElement {
@@ -14,13 +14,15 @@ impl HTMLLIElement {
         0
     }
 
-    pub fn SetValue(&mut self, _value: i32, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmllinkelement.rs b/src/components/script/dom/htmllinkelement.rs
index 6d7adf3f11a..9e7f15f9124 100644
--- a/src/components/script/dom/htmllinkelement.rs
+++ b/src/components/script/dom/htmllinkelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLLinkElement {
@@ -18,65 +18,74 @@ impl HTMLLinkElement {
     }
 
     pub fn Href(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHref(&mut self, _href: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHref(&mut self, _href: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CrossOrigin(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Rel(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetRel(&mut self, _rel: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetRel(&mut self, _rel: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Media(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMedia(&mut self, _media: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMedia(&mut self, _media: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Hreflang(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHreflang(&mut self, _href: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHreflang(&mut self, _href: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Charset(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCharset(&mut self, _charset: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCharset(&mut self, _charset: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Rev(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetRev(&mut self, _rev: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetRev(&mut self, _rev: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Target(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetTarget(&mut self, _target: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetTarget(&mut self, _target: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlmapelement.rs b/src/components/script/dom/htmlmapelement.rs
index f4157f2d65a..5e130fec014 100644
--- a/src/components/script/dom/htmlmapelement.rs
+++ b/src/components/script/dom/htmlmapelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult, CacheableWrapper};
+use dom::bindings::utils::{DOMString, ErrorResult, CacheableWrapper};
 use dom::htmlcollection::HTMLCollection;
 use dom::htmlelement::HTMLElement;
 use js::jsapi::{JSObject, JSContext};
@@ -13,10 +13,11 @@ pub struct HTMLMapElement {
 
 impl HTMLMapElement {
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     fn get_scope_and_cx(&self) -> (*JSObject, *JSContext) {
diff --git a/src/components/script/dom/htmlmediaelement.rs b/src/components/script/dom/htmlmediaelement.rs
index 009940ac926..4a69503c279 100644
--- a/src/components/script/dom/htmlmediaelement.rs
+++ b/src/components/script/dom/htmlmediaelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::element::ElementTypeId;
 use dom::htmlelement::HTMLElement;
 
@@ -20,35 +20,38 @@ impl HTMLMediaElement {
 
 impl HTMLMediaElement {
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CurrentSrc(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn CrossOrigin(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Preload(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetPreload(&mut self, _preload: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetPreload(&mut self, _preload: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Load(&self) {
     }
 
     pub fn CanPlayType(&self, _type: &DOMString) -> DOMString {
-        null_string
+        None
     }
 
     pub fn ReadyState(&self) -> u16 {
@@ -63,7 +66,8 @@ impl HTMLMediaElement {
         0f64
     }
 
-    pub fn SetCurrentTime(&mut self, _current_time: f64, _rv: &mut ErrorResult) {
+    pub fn SetCurrentTime(&mut self, _current_time: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetDuration(&self) -> f64 {
@@ -78,14 +82,16 @@ impl HTMLMediaElement {
         0f64
     }
 
-    pub fn SetDefaultPlaybackRate(&mut self, _default_playback_rate: f64, _rv: &mut ErrorResult) {
+    pub fn SetDefaultPlaybackRate(&mut self, _default_playback_rate: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn PlaybackRate(&self) -> f64 {
         0f64
     }
 
-    pub fn SetPlaybackRate(&mut self, _playback_rate: f64, _rv: &mut ErrorResult) {
+    pub fn SetPlaybackRate(&mut self, _playback_rate: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Ended(&self) -> bool {
@@ -96,34 +102,40 @@ impl HTMLMediaElement {
         false
     }
 
-    pub fn SetAutoplay(&mut self, _autoplay: bool, _rv: &mut ErrorResult) {
+    pub fn SetAutoplay(&mut self, _autoplay: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Loop(&self) -> bool {
         false
     }
 
-    pub fn SetLoop(&mut self, _loop: bool, _rv: &mut ErrorResult) {
+    pub fn SetLoop(&mut self, _loop: bool) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn Play(&self, _rv: &mut ErrorResult) {
+    pub fn Play(&self) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn Pause(&self, _rv: &mut ErrorResult) {
+    pub fn Pause(&self) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Controls(&self) -> bool {
         false
     }
 
-    pub fn SetControls(&mut self, _controls: bool, _rv: &mut ErrorResult) {
+    pub fn SetControls(&mut self, _controls: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Volume(&self) -> f64 {
         0f64
     }
 
-    pub fn SetVolume(&mut self, _volume: f64, _rv: &mut ErrorResult) {
+    pub fn SetVolume(&mut self, _volume: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Muted(&self) -> bool {
@@ -137,6 +149,7 @@ impl HTMLMediaElement {
         false
     }
 
-    pub fn SetDefaultMuted(&mut self, _default_muted: bool, _rv: &mut ErrorResult) {
+    pub fn SetDefaultMuted(&mut self, _default_muted: bool) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlmetaelement.rs b/src/components/script/dom/htmlmetaelement.rs
index aad56ca5c58..e179af271a4 100644
--- a/src/components/script/dom/htmlmetaelement.rs
+++ b/src/components/script/dom/htmlmetaelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLMetaElement {
@@ -11,30 +11,34 @@ pub struct HTMLMetaElement {
 
 impl HTMLMetaElement {
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn HttpEquiv(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHttpEquiv(&mut self, _http_equiv: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHttpEquiv(&mut self, _http_equiv: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Content(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetContent(&mut self, _content: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetContent(&mut self, _content: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Scheme(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetScheme(&mut self, _scheme: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetScheme(&mut self, _scheme: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlmeterelement.rs b/src/components/script/dom/htmlmeterelement.rs
index 3a66308adcd..a634e0d1795 100644
--- a/src/components/script/dom/htmlmeterelement.rs
+++ b/src/components/script/dom/htmlmeterelement.rs
@@ -14,41 +14,47 @@ impl HTMLMeterElement {
         0.0
     }
 
-    pub fn SetValue(&mut self, _value: f64, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Min(&self) -> f64 {
         0.0
     }
 
-    pub fn SetMin(&mut self, _min: f64, _rv: &mut ErrorResult) {
+    pub fn SetMin(&mut self, _min: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Max(&self) -> f64 {
         0.0
     }
 
-    pub fn SetMax(&mut self, _max: f64, _rv: &mut ErrorResult) {
+    pub fn SetMax(&mut self, _max: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Low(&self) -> f64 {
         0.0
     }
 
-    pub fn SetLow(&mut self, _low: f64, _rv: &mut ErrorResult) {
+    pub fn SetLow(&mut self, _low: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn High(&self) -> f64 {
         0.0
     }
 
-    pub fn SetHigh(&mut self, _high: f64, _rv: &mut ErrorResult) {
+    pub fn SetHigh(&mut self, _high: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Optimum(&self) -> f64 {
         0.0
     }
 
-    pub fn SetOptimum(&mut self, _optimum: f64, _rv: &mut ErrorResult) {
+    pub fn SetOptimum(&mut self, _optimum: f64) -> ErrorResult {
+        Ok(())
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlmodelement.rs b/src/components/script/dom/htmlmodelement.rs
index aec788fc674..61ab800b807 100644
--- a/src/components/script/dom/htmlmodelement.rs
+++ b/src/components/script/dom/htmlmodelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLModElement {
@@ -11,16 +11,18 @@ pub struct HTMLModElement {
 
 impl HTMLModElement {
     pub fn Cite(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCite(&mut self, _cite: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCite(&mut self, _cite: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn DateTime(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDateTime(&mut self, _datetime: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDateTime(&mut self, _datetime: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlobjectelement.rs b/src/components/script/dom/htmlobjectelement.rs
index 9246c631184..4400649a90f 100644
--- a/src/components/script/dom/htmlobjectelement.rs
+++ b/src/components/script/dom/htmlobjectelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::document::AbstractDocument;
 use dom::htmlelement::HTMLElement;
 use dom::node::{AbstractNode, ScriptView};
@@ -15,31 +15,35 @@ pub struct HTMLObjectElement {
 
 impl HTMLObjectElement {
     pub fn Data(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetData(&mut self, _data: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetData(&mut self, _data: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn UseMap(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetUseMap(&mut self, _use_map: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetUseMap(&mut self, _use_map: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetForm(&self) -> Option<AbstractNode<ScriptView>> {
@@ -47,17 +51,19 @@ impl HTMLObjectElement {
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&mut self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHeight(&mut self, _height: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHeight(&mut self, _height: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetContentDocument(&self) -> Option<AbstractDocument> {
@@ -77,7 +83,7 @@ impl HTMLObjectElement {
     }
 
     pub fn ValidationMessage(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn CheckValidity(&self) -> bool {
@@ -88,76 +94,86 @@ impl HTMLObjectElement {
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
-        pub fn Archive(&self) -> DOMString {
-        null_string
+    pub fn Archive(&self) -> DOMString {
+        None
     }
 
-    pub fn SetArchive(&mut self, _archive: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetArchive(&mut self, _archive: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Code(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCode(&mut self, _code: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCode(&mut self, _code: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Declare(&self) -> bool {
         false
     }
 
-    pub fn SetDeclare(&mut self, _declare: bool, _rv: &mut ErrorResult) {
+    pub fn SetDeclare(&mut self, _declare: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Hspace(&self) -> u32 {
         0
     }
 
-    pub fn SetHspace(&mut self, _hspace: u32, _rv: &mut ErrorResult) {
+    pub fn SetHspace(&mut self, _hspace: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Standby(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetStandby(&mut self, _standby: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetStandby(&mut self, _standby: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Vspace(&self) -> u32 {
         0
     }
 
-    pub fn SetVspace(&mut self, _vspace: u32, _rv: &mut ErrorResult) {
+    pub fn SetVspace(&mut self, _vspace: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CodeBase(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCodeBase(&mut self, _codebase: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCodeBase(&mut self, _codebase: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CodeType(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCodeType(&mut self, _codetype: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCodeType(&mut self, _codetype: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Border(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBorder(&mut self, _border: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBorder(&mut self, _border: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetSVGDocument(&self) -> Option<AbstractDocument> {
         None
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlolistelement.rs b/src/components/script/dom/htmlolistelement.rs
index 970bfa9e7c9..218b9495768 100644
--- a/src/components/script/dom/htmlolistelement.rs
+++ b/src/components/script/dom/htmlolistelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLOListElement {
@@ -14,27 +14,31 @@ impl HTMLOListElement {
         false
     }
 
-    pub fn SetReversed(&self, _reversed: bool, _rv: &mut ErrorResult) {
+    pub fn SetReversed(&self, _reversed: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Start(&self) -> i32 {
         0
     }
 
-    pub fn SetStart(&mut self, _start: i32, _rv: &mut ErrorResult) {
+    pub fn SetStart(&mut self, _start: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Compact(&self) -> bool {
         false
     }
 
-    pub fn SetCompact(&self, _compact: bool, _rv: &mut ErrorResult) {
+    pub fn SetCompact(&self, _compact: bool) -> ErrorResult {
+        Ok(())
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmloptgroupelement.rs b/src/components/script/dom/htmloptgroupelement.rs
index a5beb9155e0..bdd0221ce88 100644
--- a/src/components/script/dom/htmloptgroupelement.rs
+++ b/src/components/script/dom/htmloptgroupelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLOptGroupElement {
@@ -14,13 +14,15 @@ impl HTMLOptGroupElement {
         false
     }
 
-    pub fn SetDisabled(&mut self, _disabled: bool, _rv: &mut ErrorResult) {
+    pub fn SetDisabled(&mut self, _disabled: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Label(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetLabel(&mut self, _label: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetLabel(&mut self, _label: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmloptionelement.rs b/src/components/script/dom/htmloptionelement.rs
index c8453f85747..0aa1b07a3ad 100644
--- a/src/components/script/dom/htmloptionelement.rs
+++ b/src/components/script/dom/htmloptionelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 use dom::node::{AbstractNode, ScriptView};
 
@@ -15,7 +15,8 @@ impl HTMLOptionElement {
         false
     }
 
-    pub fn SetDisabled(&mut self, _disabled: bool, _rv: &mut ErrorResult) {
+    pub fn SetDisabled(&mut self, _disabled: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetForm(&self) -> Option<AbstractNode<ScriptView>> {
@@ -23,41 +24,46 @@ impl HTMLOptionElement {
     }
 
     pub fn Label(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetLabel(&mut self, _label: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetLabel(&mut self, _label: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn DefaultSelected(&self) -> bool {
         false
     }
 
-    pub fn SetDefaultSelected(&mut self, _default_selected: bool, _rv: &mut ErrorResult) {
+    pub fn SetDefaultSelected(&mut self, _default_selected: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Selected(&self) -> bool {
         false
     }
 
-    pub fn SetSelected(&mut self, _selected: bool, _rv: &mut ErrorResult) {
+    pub fn SetSelected(&mut self, _selected: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValue(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Text(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetText(&mut self, _text: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetText(&mut self, _text: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Index(&self) -> i32 {
         0
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmloutputelement.rs b/src/components/script/dom/htmloutputelement.rs
index 934cf23883b..d6843644e1f 100644
--- a/src/components/script/dom/htmloutputelement.rs
+++ b/src/components/script/dom/htmloutputelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 use dom::node::{AbstractNode, ScriptView};
 use dom::validitystate::ValidityState;
@@ -17,28 +17,31 @@ impl HTMLOutputElement {
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn DefaultValue(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDefaultValue(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDefaultValue(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValue(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn WillValidate(&self) -> bool {
@@ -56,10 +59,11 @@ impl HTMLOutputElement {
     }
 
     pub fn ValidationMessage(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValidationMessage(&mut self, _message: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValidationMessage(&mut self, _message: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CheckValidity(&self) -> bool {
diff --git a/src/components/script/dom/htmlparagraphelement.rs b/src/components/script/dom/htmlparagraphelement.rs
index 618a22d94d9..ff0a4c51155 100644
--- a/src/components/script/dom/htmlparagraphelement.rs
+++ b/src/components/script/dom/htmlparagraphelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLParagraphElement {
@@ -11,9 +11,10 @@ pub struct HTMLParagraphElement {
 
 impl HTMLParagraphElement {
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlparamelement.rs b/src/components/script/dom/htmlparamelement.rs
index 3ec1e4ee798..e3ba463a242 100644
--- a/src/components/script/dom/htmlparamelement.rs
+++ b/src/components/script/dom/htmlparamelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLParamElement {
@@ -11,30 +11,34 @@ pub struct HTMLParamElement {
 
 impl HTMLParamElement {
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValue(&mut self, _value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ValueType(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValueType(&mut self, _value_type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValueType(&mut self, _value_type: &DOMString) -> ErrorResult {
+        Ok(())
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlpreelement.rs b/src/components/script/dom/htmlpreelement.rs
index ebdf6224273..4e5ddb49fa6 100644
--- a/src/components/script/dom/htmlpreelement.rs
+++ b/src/components/script/dom/htmlpreelement.rs
@@ -14,6 +14,7 @@ impl HTMLPreElement {
         0
     }
 
-    pub fn SetWidth(&mut self, _width: i32, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: i32) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlprogresselement.rs b/src/components/script/dom/htmlprogresselement.rs
index b4aebf5c8cd..982be3daf91 100644
--- a/src/components/script/dom/htmlprogresselement.rs
+++ b/src/components/script/dom/htmlprogresselement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{ErrorResult};
+use dom::bindings::utils::{ErrorResult, Fallible};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLProgressElement {
@@ -14,21 +14,23 @@ impl HTMLProgressElement {
         0f64
     }
 
-    pub fn SetValue(&mut self, _value: f64, _rv: &mut ErrorResult) {
+    pub fn SetValue(&mut self, _value: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Max(&self) -> f64 {
         0f64
     }
 
-    pub fn SetMax(&mut self, _max: f64, _rv: &mut ErrorResult) {
+    pub fn SetMax(&mut self, _max: f64) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Position(&self) -> f64 {
         0f64
     }
 
-    pub fn GetPositiom(&self, _rv: &mut ErrorResult) -> f64 {
-        0f64
+    pub fn GetPositiom(&self) -> Fallible<f64> {
+        Ok(0f64)
     }
 }
diff --git a/src/components/script/dom/htmlquoteelement.rs b/src/components/script/dom/htmlquoteelement.rs
index 3201ee15094..378078a85f3 100644
--- a/src/components/script/dom/htmlquoteelement.rs
+++ b/src/components/script/dom/htmlquoteelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLQuoteElement {
@@ -11,9 +11,10 @@ pub struct HTMLQuoteElement {
 
 impl HTMLQuoteElement {
     pub fn Cite(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCite(&self, _cite: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCite(&self, _cite: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlscriptelement.rs b/src/components/script/dom/htmlscriptelement.rs
index 9556955eabe..ca6debddb34 100644
--- a/src/components/script/dom/htmlscriptelement.rs
+++ b/src/components/script/dom/htmlscriptelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLScriptElement {
@@ -11,65 +11,74 @@ pub struct HTMLScriptElement {
 
 impl HTMLScriptElement {
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Charset(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCharset(&mut self, _charset: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCharset(&mut self, _charset: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Async(&self) -> bool {
         false
     }
 
-    pub fn SetAsync(&self, _async: bool, _rv: &mut ErrorResult) {
+    pub fn SetAsync(&self, _async: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Defer(&self) -> bool {
         false
     }
 
-    pub fn SetDefer(&self, _defer: bool, _rv: &mut ErrorResult) {
+    pub fn SetDefer(&self, _defer: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CrossOrigin(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCrossOrigin(&mut self, _cross_origin: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Text(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetText(&mut self, _text: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetText(&mut self, _text: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Event(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetEvent(&mut self, _event: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetEvent(&mut self, _event: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn HtmlFor(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHtmlFor(&mut self, _html_for: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHtmlFor(&mut self, _html_for: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlselectelement.rs b/src/components/script/dom/htmlselectelement.rs
index b3ef7871325..b6c7f248d20 100644
--- a/src/components/script/dom/htmlselectelement.rs
+++ b/src/components/script/dom/htmlselectelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 use dom::node::{AbstractNode, ScriptView};
 use dom::validitystate::ValidityState;
@@ -16,14 +16,16 @@ impl HTMLSelectElement {
         false
     }
 
-    pub fn SetAutofocus(&mut self, _autofocus: bool, _rv: &mut ErrorResult) {
+    pub fn SetAutofocus(&mut self, _autofocus: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Disabled(&self) -> bool {
         false
     }
 
-    pub fn SetDisabled(&mut self, _disabled: bool, _rv: &mut ErrorResult) {
+    pub fn SetDisabled(&mut self, _disabled: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetForm(&self) -> Option<AbstractNode<ScriptView>> {
@@ -34,39 +36,44 @@ impl HTMLSelectElement {
         false
     }
 
-    pub fn SetMultiple(&mut self, _multiple: bool, _rv: &mut ErrorResult) {
+    pub fn SetMultiple(&mut self, _multiple: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Required(&self) -> bool {
         false
     }
 
-    pub fn SetRequired(&mut self, _multiple: bool, _rv: &mut ErrorResult) {
+    pub fn SetRequired(&mut self, _multiple: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Size(&self) -> u32 {
         0
     }
 
-    pub fn SetSize(&mut self, _size: u32, _rv: &mut ErrorResult) {
+    pub fn SetSize(&mut self, _size: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn Length(&self) -> u32 {
         0
     }
 
-    pub fn SetLength(&mut self, _length: u32, _rv: &mut ErrorResult) {
+    pub fn SetLength(&mut self, _length: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Item(&self, _index: u32) -> Option<AbstractNode<ScriptView>> {
@@ -81,7 +88,8 @@ impl HTMLSelectElement {
         None
     }
 
-    pub fn IndexedSetter(&mut self, _index: u32, _option: Option<AbstractNode<ScriptView>>, _rv: &mut ErrorResult) {
+    pub fn IndexedSetter(&mut self, _index: u32, _option: Option<AbstractNode<ScriptView>>) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Remove_(&self) {
@@ -94,11 +102,12 @@ impl HTMLSelectElement {
         0
     }
 
-    pub fn SetSelectedIndex(&mut self, _index: i32, _rv: &mut ErrorResult) {
+    pub fn SetSelectedIndex(&mut self, _index: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetValue(&mut self, _value: &DOMString) {
@@ -119,10 +128,11 @@ impl HTMLSelectElement {
     }
 
     pub fn ValidationMessage(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetValidationMessage(&mut self, _message: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetValidationMessage(&mut self, _message: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CheckValidity(&self) -> bool {
@@ -131,4 +141,4 @@ impl HTMLSelectElement {
 
     pub fn SetCustomValidity(&mut self, _error: &DOMString) {
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/htmlsourceelement.rs b/src/components/script/dom/htmlsourceelement.rs
index 8c57fb78256..b48a42f0589 100644
--- a/src/components/script/dom/htmlsourceelement.rs
+++ b/src/components/script/dom/htmlsourceelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLSourceElement {
@@ -11,23 +11,26 @@ pub struct HTMLSourceElement {
 
 impl HTMLSourceElement {
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
     
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
     
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Media(&self) -> DOMString {
-        null_string
+        None
     }
     
-    pub fn SetMedia(&mut self, _media: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMedia(&mut self, _media: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlstyleelement.rs b/src/components/script/dom/htmlstyleelement.rs
index f79b8da679d..341fe69b2c1 100644
--- a/src/components/script/dom/htmlstyleelement.rs
+++ b/src/components/script/dom/htmlstyleelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLStyleElement {
@@ -18,23 +18,26 @@ impl HTMLStyleElement {
     }
 
     pub fn Media(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetMedia(&mut self, _media: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetMedia(&mut self, _media: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Scoped(&self) -> bool {
         false
     }
 
-    pub fn SetScoped(&self, _scoped: bool, _rv: &mut ErrorResult) {
+    pub fn SetScoped(&self, _scoped: bool) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltablecaptionelement.rs b/src/components/script/dom/htmltablecaptionelement.rs
index 3cb48190d69..3e2eb2a32e8 100644
--- a/src/components/script/dom/htmltablecaptionelement.rs
+++ b/src/components/script/dom/htmltablecaptionelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTableCaptionElement {
@@ -11,9 +11,10 @@ pub struct HTMLTableCaptionElement {
 
 impl HTMLTableCaptionElement {
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
     
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltablecellelement.rs b/src/components/script/dom/htmltablecellelement.rs
index 5a57a9ccb6d..507453cd280 100644
--- a/src/components/script/dom/htmltablecellelement.rs
+++ b/src/components/script/dom/htmltablecellelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTableCellElement {
@@ -14,104 +14,119 @@ impl HTMLTableCellElement {
         0
     }
 
-    pub fn SetColSpan(&self, _col_span: u32, _rv: &mut ErrorResult) {
+    pub fn SetColSpan(&self, _col_span: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn RowSpan(&self) -> u32 {
         0
     }
 
-    pub fn SetRowSpan(&self, _col_span: u32, _rv: &mut ErrorResult) {
+    pub fn SetRowSpan(&self, _col_span: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Headers(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHeaders(&self, _headers: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHeaders(&self, _headers: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CellIndex(&self) -> i32 {
         0
     }
 
-    pub fn GetCellIndex(&self, _cell_index: i32, _rv: &mut ErrorResult) {
+    pub fn GetCellIndex(&self, _cell_index: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Abbr(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAbbr(&self, _abbr: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAbbr(&self, _abbr: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Scope(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetScope(&self, _abbr: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetScope(&self, _abbr: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Axis(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAxis(&self, _axis: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAxis(&self, _axis: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetHeight(&self, _height: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetHeight(&self, _height: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Ch(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCh(&self, _ch: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCh(&self, _ch: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ChOff(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetChOff(&self, _ch_off: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetChOff(&self, _ch_off: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn NoWrap(&self) -> bool {
         false
     }
 
-    pub fn SetNoWrap(&self, _no_wrap: bool, _rv: &mut ErrorResult) {
+    pub fn SetNoWrap(&self, _no_wrap: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn VAlign(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetVAlign(&self, _valign: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetVAlign(&self, _valign: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn BgColor(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBgColor(&self, _bg_color: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBgColor(&self, _bg_color: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltablecolelement.rs b/src/components/script/dom/htmltablecolelement.rs
index fa27da84c18..68c931aaa78 100644
--- a/src/components/script/dom/htmltablecolelement.rs
+++ b/src/components/script/dom/htmltablecolelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTableColElement {
@@ -14,41 +14,47 @@ impl HTMLTableColElement {
         0
     }
 
-    pub fn SetSpan(&mut self, _span: u32, _rv: &mut ErrorResult) {
+    pub fn SetSpan(&mut self, _span: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Ch(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCh(&mut self, _ch: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCh(&mut self, _ch: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ChOff(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetChOff(&mut self, _ch_off: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetChOff(&mut self, _ch_off: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn VAlign(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetVAlign(&mut self, _v_align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetVAlign(&mut self, _v_align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&mut self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&mut self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltableelement.rs b/src/components/script/dom/htmltableelement.rs
index 85c038caf06..d098b7f070c 100644
--- a/src/components/script/dom/htmltableelement.rs
+++ b/src/components/script/dom/htmltableelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTableElement {
@@ -20,7 +20,8 @@ impl HTMLTableElement {
     pub fn DeleteTFoot(&self) {
     }
 
-    pub fn DeleteRow(&mut self, _index: i32, _rv: &mut ErrorResult) {
+    pub fn DeleteRow(&mut self, _index: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Sortable(&self) -> bool {
@@ -34,65 +35,74 @@ impl HTMLTableElement {
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Border(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBorder(&self, _border: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBorder(&self, _border: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Frame(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetFrame(&self, _frame: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetFrame(&self, _frame: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Rules(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetRules(&self, _rules: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetRules(&self, _rules: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Summary(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSummary(&self, _summary: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSummary(&self, _summary: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Width(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWidth(&self, _width: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWidth(&self, _width: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn BgColor(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBgColor(&self, _bg_color: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBgColor(&self, _bg_color: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CellPadding(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCellPadding(&self, _cell_padding: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCellPadding(&self, _cell_padding: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn CellSpacing(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCellSpacing(&self, _cell_spacing: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCellSpacing(&self, _cell_spacing: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltablerowelement.rs b/src/components/script/dom/htmltablerowelement.rs
index 8286cd5ac4a..f1ab0a33a3b 100644
--- a/src/components/script/dom/htmltablerowelement.rs
+++ b/src/components/script/dom/htmltablerowelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTableRowElement {
@@ -26,41 +26,47 @@ impl HTMLTableRowElement {
         0
     }
 
-    pub fn DeleteCell(&mut self, _index: i32, _rv: &mut ErrorResult) {
+    pub fn DeleteCell(&mut self, _index: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Ch(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCh(&self, _ch: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCh(&self, _ch: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ChOff(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetChOff(&self, _ch_off: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetChOff(&self, _ch_off: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn VAlign(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetVAlign(&self, _v_align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetVAlign(&self, _v_align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn BgColor(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetBgColor(&self, _bg_color: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetBgColor(&self, _bg_color: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltablesectionelement.rs b/src/components/script/dom/htmltablesectionelement.rs
index bf0bda484d6..d42f4cb514a 100644
--- a/src/components/script/dom/htmltablesectionelement.rs
+++ b/src/components/script/dom/htmltablesectionelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTableSectionElement {
@@ -10,34 +10,39 @@ pub struct HTMLTableSectionElement {
 }
 
 impl HTMLTableSectionElement {
-    pub fn DeleteRow(&mut self, _index: i32, _rv: &mut ErrorResult) {
+    pub fn DeleteRow(&mut self, _index: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Align(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetAlign(&mut self, _align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetAlign(&mut self, _align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Ch(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetCh(&mut self, _ch: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetCh(&mut self, _ch: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ChOff(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetChOff(&mut self, _ch_off: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetChOff(&mut self, _ch_off: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn VAlign(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetVAlign(&mut self, _v_align: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetVAlign(&mut self, _v_align: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltextareaelement.rs b/src/components/script/dom/htmltextareaelement.rs
index 55bbb9ee4da..377609797de 100644
--- a/src/components/script/dom/htmltextareaelement.rs
+++ b/src/components/script/dom/htmltextareaelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult, Fallible};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTextAreaElement {
@@ -14,88 +14,99 @@ impl HTMLTextAreaElement {
         false
     }
 
-    pub fn SetAutofocus(&mut self, _autofocus: bool, _rv: &mut ErrorResult) {
+    pub fn SetAutofocus(&mut self, _autofocus: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Cols(&self) -> u32 {
         0
     }
 
-    pub fn SetCols(&self, _cols: u32, _rv: &mut ErrorResult) {
+    pub fn SetCols(&self, _cols: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Disabled(&self) -> bool {
         false
     }
 
-    pub fn SetDisabled(&mut self, _disabled: bool, _rv: &mut ErrorResult) {
+    pub fn SetDisabled(&mut self, _disabled: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn MaxLength(&self) -> i32 {
         0
     }
 
-    pub fn SetMaxLength(&self, _max_length: i32, _rv: &mut ErrorResult) {
+    pub fn SetMaxLength(&self, _max_length: i32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetName(&mut self, _name: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetName(&mut self, _name: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Placeholder(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetPlaceholder(&mut self, _placeholder: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetPlaceholder(&mut self, _placeholder: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ReadOnly(&self) -> bool {
         false
     }
 
-    pub fn SetReadOnly(&mut self, _read_only: bool, _rv: &mut ErrorResult) {
+    pub fn SetReadOnly(&mut self, _read_only: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Required(&self) -> bool {
         false
     }
 
-    pub fn SetRequired(&mut self, _required: bool, _rv: &mut ErrorResult) {
+    pub fn SetRequired(&mut self, _required: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Rows(&self) -> u32 {
         0
     }
 
-    pub fn SetRows(&self, _rows: u32, _rv: &mut ErrorResult) {
+    pub fn SetRows(&self, _rows: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Wrap(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetWrap(&mut self, _wrap: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetWrap(&mut self, _wrap: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetType(&mut self, _type: &DOMString) {
     }
 
     pub fn DefaultValue(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetDefaultValue(&mut self, _default_value: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDefaultValue(&mut self, _default_value: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Value(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetValue(&mut self, _value: &DOMString) {
@@ -105,18 +116,20 @@ impl HTMLTextAreaElement {
         0
     }
 
-    pub fn SetTextLength(&self, _text_length: u32, _rv: &mut ErrorResult) {
+    pub fn SetTextLength(&self, _text_length: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn WillValidate(&self) -> bool {
         false
     }
 
-    pub fn SetWillValidate(&mut self, _will_validate: bool, _rv: &mut ErrorResult) {
+    pub fn SetWillValidate(&mut self, _will_validate: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ValidationMessage(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn CheckValidity(&self) -> bool {
@@ -129,25 +142,28 @@ impl HTMLTextAreaElement {
     pub fn Select(&self) {
     }
 
-    pub fn GetSelectionStart(&self, _rv: &mut ErrorResult) -> u32 {
-        0
+    pub fn GetSelectionStart(&self) -> Fallible<u32> {
+        Ok(0)
     }
 
-    pub fn SetSelectionStart(&self, _selection_start: u32, _rv: &mut ErrorResult) {
+    pub fn SetSelectionStart(&self, _selection_start: u32) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn GetSelectionEnd(&self, _rv: &mut ErrorResult) -> u32 {
-        0
+    pub fn GetSelectionEnd(&self) -> Fallible<u32> {
+        Ok(0)
     }
 
-    pub fn SetSelectionEnd(&self, _selection_end: u32, _rv: &mut ErrorResult) {
+    pub fn SetSelectionEnd(&self, _selection_end: u32) -> ErrorResult {
+        Ok(())
     }
 
-    pub fn GetSelectionDirection(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetSelectionDirection(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn SetSelectionDirection(&self, _selection_direction: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSelectionDirection(&self, _selection_direction: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn SetRangeText(&self, _replacement: &DOMString) {
diff --git a/src/components/script/dom/htmltimeelement.rs b/src/components/script/dom/htmltimeelement.rs
index 2b3b5be795d..82b535e66c4 100644
--- a/src/components/script/dom/htmltimeelement.rs
+++ b/src/components/script/dom/htmltimeelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTimeElement {
@@ -11,9 +11,10 @@ pub struct HTMLTimeElement {
 
 impl HTMLTimeElement {
     pub fn DateTime(&self) -> DOMString {
-        null_string
+        None
     }
     
-    pub fn SetDateTime(&mut self, _dateTime: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetDateTime(&mut self, _dateTime: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltitleelement.rs b/src/components/script/dom/htmltitleelement.rs
index aa5c920dc18..829c8c86be7 100644
--- a/src/components/script/dom/htmltitleelement.rs
+++ b/src/components/script/dom/htmltitleelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTitleElement {
@@ -11,9 +11,10 @@ pub struct HTMLTitleElement {
 
 impl HTMLTitleElement {
     pub fn Text(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetText(&mut self, _text: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetText(&mut self, _text: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmltrackelement.rs b/src/components/script/dom/htmltrackelement.rs
index 40ba4e0f4cb..0148b01cb81 100644
--- a/src/components/script/dom/htmltrackelement.rs
+++ b/src/components/script/dom/htmltrackelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLTrackElement {
@@ -11,38 +11,43 @@ pub struct HTMLTrackElement {
 
 impl HTMLTrackElement {
     pub fn Kind(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetKind(&mut self, _kind: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetKind(&mut self, _kind: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Src(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrc(&mut self, _src: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrc(&mut self, _src: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Srclang(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetSrclang(&mut self, _srclang: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetSrclang(&mut self, _srclang: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Label(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetLabel(&mut self, _label: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetLabel(&mut self, _label: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Default(&self) -> bool {
         false
     }
 
-    pub fn SetDefault(&mut self, _default: bool, _rv: &mut ErrorResult) {
+    pub fn SetDefault(&mut self, _default: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn ReadyState(&self) -> u16 {
diff --git a/src/components/script/dom/htmlulistelement.rs b/src/components/script/dom/htmlulistelement.rs
index 9299d723b9c..1135ba98bcb 100644
--- a/src/components/script/dom/htmlulistelement.rs
+++ b/src/components/script/dom/htmlulistelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlelement::HTMLElement;
 
 pub struct HTMLUListElement {
@@ -14,13 +14,15 @@ impl HTMLUListElement {
         false
     }
     
-    pub fn SetCompact(&mut self, _compact: bool, _rv: &mut ErrorResult) {
+    pub fn SetCompact(&mut self, _compact: bool) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Type(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetType(&mut self, _type: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetType(&mut self, _type: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/htmlvideoelement.rs b/src/components/script/dom/htmlvideoelement.rs
index 19a6a546fed..59d819b2ba4 100644
--- a/src/components/script/dom/htmlvideoelement.rs
+++ b/src/components/script/dom/htmlvideoelement.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, null_string, ErrorResult};
+use dom::bindings::utils::{DOMString, ErrorResult};
 use dom::htmlmediaelement::HTMLMediaElement;
 
 pub struct HTMLVideoElement {
@@ -14,14 +14,16 @@ impl HTMLVideoElement {
         0
     }
 
-    pub fn SetWidth(&mut self, _width: u32, _rv: &ErrorResult) {
+    pub fn SetWidth(&mut self, _width: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn Height(&self) -> u32 {
         0
     }
 
-    pub fn SetHeight(&mut self, _height: u32, _rv: &ErrorResult) {
+    pub fn SetHeight(&mut self, _height: u32) -> ErrorResult {
+        Ok(())
     }
 
     pub fn VideoWidth(&self) -> u32 {
@@ -33,9 +35,10 @@ impl HTMLVideoElement {
     }
 
     pub fn Poster(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetPoster(&mut self, _poster: &DOMString, _rv: &ErrorResult) {
+    pub fn SetPoster(&mut self, _poster: &DOMString) -> ErrorResult {
+        Ok(())
     }
 }
diff --git a/src/components/script/dom/mouseevent.rs b/src/components/script/dom/mouseevent.rs
index fe986d581a0..6a455279840 100644
--- a/src/components/script/dom/mouseevent.rs
+++ b/src/components/script/dom/mouseevent.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::MouseEventBinding;
-use dom::bindings::utils::{ErrorResult, DOMString};
+use dom::bindings::utils::{ErrorResult, Fallible, DOMString};
 use dom::bindings::utils::{CacheableWrapper, WrapperCache, BindingObject, DerivedWrapper};
 use dom::eventtarget::EventTarget;
 use dom::uievent::UIEvent;
@@ -54,12 +54,11 @@ impl MouseEvent {
 
     pub fn Constructor(_owner: @mut Window,
                        type_: &DOMString,
-                       init: &MouseEventBinding::MouseEventInit,
-                       _rv: &mut ErrorResult) -> @mut MouseEvent {
-        @mut MouseEvent::new(type_, init.bubbles, init.cancelable, init.view, init.detail,
-                             init.screenX, init.screenY, init.clientX, init.clientY,
-                             init.ctrlKey, init.shiftKey, init.altKey, init.metaKey,
-                             init.button, init.buttons, init.relatedTarget)
+                       init: &MouseEventBinding::MouseEventInit) -> Fallible<@mut MouseEvent> {
+        Ok(@mut MouseEvent::new(type_, init.bubbles, init.cancelable, init.view, init.detail,
+                                init.screenX, init.screenY, init.clientX, init.clientY,
+                                init.ctrlKey, init.shiftKey, init.altKey, init.metaKey,
+                                init.button, init.buttons, init.relatedTarget))
     }
 
     pub fn ScreenX(&self) -> i32 {
@@ -127,8 +126,7 @@ impl MouseEvent {
                           shiftKeyArg: bool,
                           metaKeyArg: bool,
                           buttonArg: u16,
-                          relatedTargetArg: Option<@mut EventTarget>,
-                          _rv: &mut ErrorResult) {
+                          relatedTargetArg: Option<@mut EventTarget>) -> ErrorResult {
         self.parent.InitUIEvent(typeArg, canBubbleArg, cancelableArg, viewArg, detailArg);
         self.screen_x = screenXArg;
         self.screen_y = screenYArg;
@@ -140,6 +138,7 @@ impl MouseEvent {
         self.meta_key = metaKeyArg;
         self.button = buttonArg;
         self.related_target = relatedTargetArg;
+        Ok(())
     }
 }
 
diff --git a/src/components/script/dom/navigator.rs b/src/components/script/dom/navigator.rs
index f6a98b59a89..144f5a548b5 100644
--- a/src/components/script/dom/navigator.rs
+++ b/src/components/script/dom/navigator.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::utils::{WrapperCache, BindingObject, CacheableWrapper};
-use dom::bindings::utils::{DOMString, ErrorResult, str, null_string};
+use dom::bindings::utils::{DOMString, Fallible};
 use dom::bindings::codegen::NavigatorBinding;
 use script_task::{page_from_context};
 
@@ -23,35 +23,35 @@ impl Navigator {
     }
 
     pub fn DoNotTrack(&self) -> DOMString {
-        str(~"unspecified")
+        Some(~"unspecified")
     }
 
     pub fn Vendor(&self) -> DOMString {
-        str(~"") // Like Gecko
+        Some(~"") // Like Gecko
     }
 
     pub fn VendorSub(&self) -> DOMString {
-        str(~"") // Like Gecko
+        Some(~"") // Like Gecko
     }
 
     pub fn Product(&self) -> DOMString {
-        str(~"Gecko") // This is supposed to be constant, see webidl.
+        Some(~"Gecko") // This is supposed to be constant, see webidl.
     }
 
     pub fn ProductSub(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn CookieEnabled(&self) -> bool {
         false
     }
 
-    pub fn GetBuildID(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetBuildID(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn JavaEnabled(&self, _rv: &mut ErrorResult) -> bool {
-        false
+    pub fn JavaEnabled(&self) -> Fallible<bool> {
+        Ok(false)
     }
 
     pub fn TaintEnabled(&self) -> bool {
@@ -59,27 +59,27 @@ impl Navigator {
     }
 
     pub fn AppName(&self) -> DOMString {
-        str(~"Netscape") // Like Gecko/Webkit
+        Some(~"Netscape") // Like Gecko/Webkit
     }
 
-    pub fn GetAppCodeName(&self, _rv: &mut ErrorResult) -> DOMString {
-        str(~"Mozilla") // Like Gecko/Webkit
+    pub fn GetAppCodeName(&self) -> Fallible<DOMString> {
+        Ok(Some(~"Mozilla")) // Like Gecko/Webkit
     }
 
-    pub fn GetAppVersion(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetAppVersion(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn GetPlatform(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetPlatform(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
-    pub fn GetUserAgent(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetUserAgent(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 
     pub fn GetLanguage(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn OnLine(&self) -> bool {
@@ -105,4 +105,4 @@ impl BindingObject for Navigator {
             Some((*page).frame.get_ref().window as @mut CacheableWrapper)
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/components/script/dom/node.rs b/src/components/script/dom/node.rs
index 289d571ea86..d40b85be8e6 100644
--- a/src/components/script/dom/node.rs
+++ b/src/components/script/dom/node.rs
@@ -5,9 +5,8 @@
 //! The core DOM types. Defines the basic DOM hierarchy as well as all the HTML elements.
 
 use dom::bindings::node;
-use dom::bindings::utils::{WrapperCache, DOMString, null_string, str, ErrorResult, NotFound, HierarchyRequest};
-use dom::bindings::utils::{BindingObject, CacheableWrapper, rust_box};
-use dom::bindings;
+use dom::bindings::utils::{WrapperCache, DOMString, ErrorResult, Fallible, NotFound, HierarchyRequest};
+use dom::bindings::utils::{BindingObject, CacheableWrapper, null_str_as_empty};
 use dom::characterdata::CharacterData;
 use dom::document::AbstractDocument;
 use dom::element::{Element, ElementTypeId, HTMLImageElementTypeId, HTMLIframeElementTypeId};
@@ -19,6 +18,7 @@ use dom::text::Text;
 use std::cast;
 use std::cast::transmute;
 use std::libc::c_void;
+use std::unstable::raw::Box;
 use extra::arc::Arc;
 use js::jsapi::{JSObject, JSContext};
 use netsurfcss::util::VoidPtrLike;
@@ -170,7 +170,7 @@ impl<'self, View> AbstractNode<View> {
     /// Allow consumers to recreate an AbstractNode from the raw boxed type.
     /// Must only be used in situations where the boxed type is in the inheritance
     /// chain for nodes.
-    pub fn from_box<T>(ptr: *mut rust_box<T>) -> AbstractNode<View> {
+    pub fn from_box<T>(ptr: *mut Box<T>) -> AbstractNode<View> {
         AbstractNode {
             obj: ptr as *mut Node<View>
         }
@@ -219,12 +219,12 @@ impl<'self, View> AbstractNode<View> {
 
     pub fn transmute<T, R>(self, f: &fn(&T) -> R) -> R {
         unsafe {
-            let node_box: *mut bindings::utils::rust_box<Node<View>> = transmute(self.obj);
-            let node = &mut (*node_box).payload;
+            let node_box: *mut Box<Node<View>> = transmute(self.obj);
+            let node = &mut (*node_box).data;
             let old = node.abstract;
             node.abstract = Some(self);
-            let box: *bindings::utils::rust_box<T> = transmute(self.obj);
-            let rv = f(&(*box).payload);
+            let box: *Box<T> = transmute(self.obj);
+            let rv = f(&(*box).data);
             node.abstract = old;
             rv
         }
@@ -232,12 +232,12 @@ impl<'self, View> AbstractNode<View> {
 
     pub fn transmute_mut<T, R>(self, f: &fn(&mut T) -> R) -> R {
         unsafe {
-            let node_box: *mut bindings::utils::rust_box<Node<View>> = transmute(self.obj);
-            let node = &mut (*node_box).payload;
+            let node_box: *mut Box<Node<View>> = transmute(self.obj);
+            let node = &mut (*node_box).data;
             let old = node.abstract;
             node.abstract = Some(self);
-            let box: *bindings::utils::rust_box<T> = transmute(self.obj);
-            let rv = f(cast::transmute(&(*box).payload));
+            let box: *Box<T> = transmute(self.obj);
+            let rv = f(cast::transmute(&(*box).data));
             node.abstract = old;
             rv
         }
@@ -516,11 +516,11 @@ impl Node<ScriptView> {
     }
 
     pub fn NodeName(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn GetBaseURI(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn GetOwnerDocument(&self) -> Option<AbstractDocument> {
@@ -556,10 +556,11 @@ impl Node<ScriptView> {
     }
 
     pub fn GetNodeValue(&self) -> DOMString {
-        null_string
+        None
     }
 
-    pub fn SetNodeValue(&mut self, _val: &DOMString, _rv: &mut ErrorResult) {
+    pub fn SetNodeValue(&mut self, _val: &DOMString) -> ErrorResult {
+        Ok(())
     }
 
     pub fn GetTextContent(&self, abstract_self: AbstractNode<ScriptView>) -> DOMString {
@@ -570,11 +571,11 @@ impl Node<ScriptView> {
                 if node.is_text() {
                     do node.with_imm_text() |text| {
                         let s = text.parent.Data();
-                        content = content + s.to_str();
+                        content = content + null_str_as_empty(&s);
                     }
                 }
             }
-            str(content)
+            Some(content)
           }
           CommentNodeTypeId | TextNodeTypeId => {
             do abstract_self.with_imm_characterdata() |characterdata| {
@@ -582,7 +583,7 @@ impl Node<ScriptView> {
             }
           }
           DoctypeNodeTypeId => {
-            null_string
+            None
           }
         }
     }
@@ -592,24 +593,22 @@ impl Node<ScriptView> {
                        abstract_self: AbstractNode<ScriptView>,
                        node: Option<AbstractNode<ScriptView>>) {
         //FIXME: We should batch document notifications that occur here
-        let mut rv = Ok(());
         for child in abstract_self.children() {
-            self.RemoveChild(abstract_self, child, &mut rv);
+            self.RemoveChild(abstract_self, child);
         }
         match node {
             None => {},
             Some(node) => {
-                self.AppendChild(abstract_self, node, &mut rv);
+                self.AppendChild(abstract_self, node);
             }
         }
     }
 
     pub fn SetTextContent(&mut self,
                           abstract_self: AbstractNode<ScriptView>,
-                          value: &DOMString,
-                          _rv: &mut ErrorResult) {
+                          value: &DOMString) -> ErrorResult {
         let is_empty = match value {
-            &str(~"") | &null_string => true,
+            &Some(~"") | &None => true,
             _ => false
         };
         match self.type_id {
@@ -628,7 +627,7 @@ impl Node<ScriptView> {
             self.wait_until_safe_to_modify_dom();
 
             do abstract_self.with_mut_characterdata() |characterdata| {
-                characterdata.data = value.to_str();
+                characterdata.data = null_str_as_empty(value);
 
                 // Notify the document that the content of this node is different
                 for doc in self.owner_doc.iter() {
@@ -640,9 +639,10 @@ impl Node<ScriptView> {
           }
           DoctypeNodeTypeId => {}
         }
+        Ok(())
     }
 
-    pub fn InsertBefore(&mut self, _node: AbstractNode<ScriptView>, _child: Option<AbstractNode<ScriptView>>, _rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+    pub fn InsertBefore(&mut self, _node: AbstractNode<ScriptView>, _child: Option<AbstractNode<ScriptView>>) -> Fallible<AbstractNode<ScriptView>> {
         fail!("stub")
     }
 
@@ -656,8 +656,7 @@ impl Node<ScriptView> {
 
     pub fn AppendChild(&mut self,
                        abstract_self: AbstractNode<ScriptView>,
-                       node: AbstractNode<ScriptView>,
-                       rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+                       node: AbstractNode<ScriptView>) -> Fallible<AbstractNode<ScriptView>> {
         fn is_hierarchy_request_err(this_node: AbstractNode<ScriptView>,
                                    new_child: AbstractNode<ScriptView>) -> bool {
             if new_child.is_doctype() {
@@ -680,35 +679,32 @@ impl Node<ScriptView> {
         }
 
         if is_hierarchy_request_err(abstract_self, node) {
-            *rv = Err(HierarchyRequest);
+            return Err(HierarchyRequest);
         }
 
         // TODO: Should we handle WRONG_DOCUMENT_ERR here?
 
-        if rv.is_ok() {
-            self.wait_until_safe_to_modify_dom();
+        self.wait_until_safe_to_modify_dom();
 
-            // If the node already exists it is removed from current parent node.
-            node.parent_node().map(|parent| parent.remove_child(node));
-            abstract_self.add_child(node);
-            match self.owner_doc {
-                Some(doc) => do node.with_mut_base |node| {
-                    node.add_to_doc(doc);
-                },
-                None => ()
-            }
+        // If the node already exists it is removed from current parent node.
+        node.parent_node().map(|parent| parent.remove_child(node));
+        abstract_self.add_child(node);
+        match self.owner_doc {
+            Some(doc) => do node.with_mut_base |node| {
+                node.add_to_doc(doc);
+            },
+            None => ()
         }
-        node
+        Ok(node)
     }
 
-    pub fn ReplaceChild(&mut self, _node: AbstractNode<ScriptView>, _child: AbstractNode<ScriptView>, _rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+    pub fn ReplaceChild(&mut self, _node: AbstractNode<ScriptView>, _child: AbstractNode<ScriptView>) -> Fallible<AbstractNode<ScriptView>> {
         fail!("stub")
     }
 
     pub fn RemoveChild(&mut self,
                        abstract_self: AbstractNode<ScriptView>,
-                       node: AbstractNode<ScriptView>,
-                       rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+                       node: AbstractNode<ScriptView>) -> Fallible<AbstractNode<ScriptView>> {
         fn is_not_found_err(this_node: AbstractNode<ScriptView>,
                             old_child: AbstractNode<ScriptView>) -> bool {
             match old_child.parent_node() {
@@ -718,21 +714,20 @@ impl Node<ScriptView> {
         }
 
         if is_not_found_err(abstract_self, node) {
-            *rv = Err(NotFound);
+            return Err(NotFound);
         }
-        if rv.is_ok() {
-            self.wait_until_safe_to_modify_dom();
 
-            abstract_self.remove_child(node);
-            self.remove_from_doc();
-        }
-        node
+        self.wait_until_safe_to_modify_dom();
+
+        abstract_self.remove_child(node);
+        self.remove_from_doc();
+        Ok(node)
     }
 
     pub fn Normalize(&mut self) {
     }
 
-    pub fn CloneNode(&self, _deep: bool, _rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+    pub fn CloneNode(&self, _deep: bool) -> Fallible<AbstractNode<ScriptView>> {
         fail!("stub")
     }
 
@@ -749,11 +744,11 @@ impl Node<ScriptView> {
     }
 
     pub fn LookupPrefix(&self, _prefix: &DOMString) -> DOMString {
-        null_string
+        None
     }
 
     pub fn LookupNamespaceURI(&self, _namespace: &DOMString) -> DOMString {
-        null_string
+        None
     }
 
     pub fn IsDefaultNamespace(&self, _namespace: &DOMString) -> bool {
@@ -761,15 +756,15 @@ impl Node<ScriptView> {
     }
 
     pub fn GetNamespaceURI(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn GetPrefix(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn GetLocalName(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn HasAttributes(&self) -> bool {
diff --git a/src/components/script/dom/text.rs b/src/components/script/dom/text.rs
index 456e1084538..ae9cf24e02e 100644
--- a/src/components/script/dom/text.rs
+++ b/src/components/script/dom/text.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::{DOMString, ErrorResult, null_string};
+use dom::bindings::utils::{DOMString, Fallible, null_str_as_empty};
 use dom::characterdata::CharacterData;
 use dom::node::{AbstractNode, ScriptView, Node, TextNodeTypeId};
 use dom::window::Window;
@@ -20,16 +20,16 @@ impl Text {
         }
     }
 
-    pub fn Constructor(owner: @mut Window, text: &DOMString, _rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+    pub fn Constructor(owner: @mut Window, text: &DOMString) -> Fallible<AbstractNode<ScriptView>> {
         let cx = owner.page.js_info.get_ref().js_compartment.cx.ptr;
-        unsafe { Node::as_abstract_node(cx, @Text::new(text.to_str())) }
+        unsafe { Ok(Node::as_abstract_node(cx, @Text::new(null_str_as_empty(text)))) }
     }
 
-    pub fn SplitText(&self, _offset: u32, _rv: &mut ErrorResult) -> AbstractNode<ScriptView> {
+    pub fn SplitText(&self, _offset: u32) -> Fallible<AbstractNode<ScriptView>> {
         fail!("unimplemented")
     }
 
-    pub fn GetWholeText(&self, _rv: &mut ErrorResult) -> DOMString {
-        null_string
+    pub fn GetWholeText(&self) -> Fallible<DOMString> {
+        Ok(None)
     }
 }
diff --git a/src/components/script/dom/uievent.rs b/src/components/script/dom/uievent.rs
index c9d67c8d7f9..35cf161fbbc 100644
--- a/src/components/script/dom/uievent.rs
+++ b/src/components/script/dom/uievent.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::UIEventBinding;
-use dom::bindings::utils::{ErrorResult, DOMString};
+use dom::bindings::utils::{DOMString, Fallible};
 use dom::bindings::utils::{CacheableWrapper, WrapperCache, BindingObject, DerivedWrapper};
 use dom::node::{AbstractNode, ScriptView};
 use dom::event::Event;
@@ -39,10 +39,9 @@ impl UIEvent {
 
     pub fn Constructor(_owner: @mut Window,
                        type_: &DOMString,
-                       init: &UIEventBinding::UIEventInit,
-                       _rv: &mut ErrorResult) -> @mut UIEvent {
-        @mut UIEvent::new(type_, init.parent.bubbles, init.parent.cancelable,
-                          init.view, init.detail)
+                       init: &UIEventBinding::UIEventInit) -> Fallible<@mut UIEvent> {
+        Ok(@mut UIEvent::new(type_, init.parent.bubbles, init.parent.cancelable,
+                             init.view, init.detail))
     }
 
     pub fn GetView(&self) -> Option<@mut WindowProxy> {
@@ -59,8 +58,7 @@ impl UIEvent {
                        cancelable: bool,
                        view: Option<@mut WindowProxy>,
                        detail: i32) {
-        let mut rv = Ok(());
-        self.parent.InitEvent(type_, can_bubble, cancelable, &mut rv);
+        self.parent.InitEvent(type_, can_bubble, cancelable);
         self.can_bubble = can_bubble;
         self.cancelable = cancelable;
         self.view = view;
diff --git a/src/components/script/dom/window.rs b/src/components/script/dom/window.rs
index 2eac2f46966..a7bae87a618 100644
--- a/src/components/script/dom/window.rs
+++ b/src/components/script/dom/window.rs
@@ -3,8 +3,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::codegen::WindowBinding;
-use dom::bindings::utils::{WrapperCache, DOMString, null_string, Traceable};
-use dom::bindings::utils::{CacheableWrapper, BindingObject};
+use dom::bindings::utils::{WrapperCache, DOMString, Traceable};
+use dom::bindings::utils::{CacheableWrapper, BindingObject, null_str_as_empty};
 use dom::document::AbstractDocument;
 use dom::node::{AbstractNode, ScriptView};
 use dom::navigator::Navigator;
@@ -69,7 +69,7 @@ pub struct TimerData {
 impl Window {
     pub fn Alert(&self, s: &DOMString) {
         // Right now, just print to the console
-        io::println(fmt!("ALERT: %s", s.to_str()));
+        io::println(fmt!("ALERT: %s", null_str_as_empty(s)));
     }
 
     pub fn Close(&self) {
@@ -81,14 +81,14 @@ impl Window {
     }
 
     pub fn Name(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetName(&self, _name: &DOMString) {
     }
 
     pub fn Status(&self) -> DOMString {
-        null_string
+        None
     }
 
     pub fn SetStatus(&self, _status: &DOMString) {
@@ -123,7 +123,7 @@ impl Window {
     }
 
     pub fn Prompt(&self, _message: &DOMString, _default: &DOMString) -> DOMString {
-        null_string
+        None
     }
 
     pub fn Print(&self) {
diff --git a/src/components/script/html/hubbub_html_parser.rs b/src/components/script/html/hubbub_html_parser.rs
index d73db7f08cf..8696f594970 100644
--- a/src/components/script/html/hubbub_html_parser.rs
+++ b/src/components/script/html/hubbub_html_parser.rs
@@ -2,7 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use dom::bindings::utils::str;
 use dom::element::*;
 use dom::htmlelement::HTMLElement;
 use dom::htmlheadingelement::{Heading1, Heading2, Heading3, Heading4, Heading5, Heading6};
@@ -374,7 +373,7 @@ pub fn parse_html(cx: *JSContext,
             debug!("-- attach attrs");
             do node.as_mut_element |element| {
                 for attr in tag.attributes.iter() {
-                    element.set_attr(node, &str(attr.name.clone()), &str(attr.value.clone()));
+                    element.set_attr(node, &Some(attr.name.clone()), &Some(attr.value.clone()));
                 }
             }