diff --git a/src/rust-mozjs b/src/rust-mozjs
index de66662c301..e2b17f323b0 160000
--- a/src/rust-mozjs
+++ b/src/rust-mozjs
@@ -1 +1 @@
-Subproject commit de66662c301b2c00dacabdf0d82adf22d16232b4
+Subproject commit e2b17f323b0ab2d6a2d806d114bd1e61f3b1ba50
diff --git a/src/servo/dom/bindings/element.rs b/src/servo/dom/bindings/element.rs
index e5729089dd9..7bf59808d33 100644
--- a/src/servo/dom/bindings/element.rs
+++ b/src/servo/dom/bindings/element.rs
@@ -97,8 +97,10 @@ extern fn HTMLImageElement_setWidth(cx: *JSContext, _argc: c_uint, vp: *mut jsva
         match nd.kind {
           ~Element(ed) => {
             match ed.kind {
-              ~HTMLImageElement(img) =>
-                img.size.width = px_to_au(RUST_JSVAL_TO_INT(*vp) as int),
+              ~HTMLImageElement(img) => {
+                let arg = ptr::offset(JS_ARGV(cx, unsafe::reinterpret_cast(&vp)), 0);
+                img.size.width = px_to_au(RUST_JSVAL_TO_INT(*arg) as int)
+              },
               _ => fail ~"why is this not an image element?"
             }
           }
diff --git a/src/servo/dom/bindings/utils.rs b/src/servo/dom/bindings/utils.rs
index dd7d89e4018..af1036e0a0c 100644
--- a/src/servo/dom/bindings/utils.rs
+++ b/src/servo/dom/bindings/utils.rs
@@ -79,13 +79,13 @@ fn get_compartment(cx: *JSContext) -> *bare_compartment {
     }
 }
 
-extern fn has_instance(_cx: *JSContext, obj: *JSObject, v: *jsval, bp: *mut JSBool) -> JSBool {
+extern fn has_instance(_cx: *JSContext, obj: **JSObject, v: *jsval, bp: *mut JSBool) -> JSBool {
     //XXXjdm this is totally broken for non-object values
     let mut o = RUST_JSVAL_TO_OBJECT(unsafe {*v});
-    let clasp = JS_GetClass(obj);
+    let obj = unsafe {*obj};
     unsafe { *bp = 0; }
     while o.is_not_null() {
-        if JS_GetClass(o) == clasp {
+        if o == obj {
             unsafe { *bp = 1; }
             break;
         }
@@ -95,7 +95,7 @@ extern fn has_instance(_cx: *JSContext, obj: *JSObject, v: *jsval, bp: *mut JSBo
 }
 
 fn prototype_jsclass(name: ~str) -> fn(bare_compartment) -> JSClass {
-    return fn@(compartment: bare_compartment) -> JSClass {
+    |compartment: bare_compartment, copy name| {
         {name: compartment.add_name(name),
          flags: 0,
          addProperty: GetJSClassHookStubPointer(PROPERTY_STUB) as *u8,
@@ -119,12 +119,12 @@ fn prototype_jsclass(name: ~str) -> fn(bare_compartment) -> JSClass {
                     null(), null(), null(), null(), null(),  // 30
                     null(), null(), null(), null(), null(),  // 35
                     null(), null(), null(), null(), null())} // 40
-    };
+    }
 }
 
 fn instance_jsclass(name: ~str, finalize: *u8)
     -> fn(bare_compartment) -> JSClass {
-    return fn@(compartment: bare_compartment) -> JSClass {
+    |compartment: bare_compartment, copy name| {
         {name: compartment.add_name(name),
          flags: JSCLASS_HAS_RESERVED_SLOTS(1),
          addProperty: GetJSClassHookStubPointer(PROPERTY_STUB) as *u8,
@@ -148,7 +148,7 @@ fn instance_jsclass(name: ~str, finalize: *u8)
                     null(), null(), null(), null(), null(),  // 30
                     null(), null(), null(), null(), null(),  // 35
                     null(), null(), null(), null(), null())} // 40
-    };
+    }
 }
 
 fn define_empty_prototype(name: ~str, proto: Option<~str>, compartment: bare_compartment)
diff --git a/src/test/test_image_getter.js b/src/test/test_image_getter.js
index cd94d71639a..ea3763c5c37 100644
--- a/src/test/test_image_getter.js
+++ b/src/test/test_image_getter.js
@@ -1,15 +1,16 @@
 function setWidth(w, i) {
-  var elem = document.documentElement.firstChild;
   elem.width = w;
-  debug(elem.width);
+  window.alert(elem.width);
   w += i;
   if (w == 0 || w == 1000)
     i *= -1;
   window.setTimeout(function() { setWidth(w, i); }, 50);
 }
 
-var elem = document.documentElement.firstChild;
-debug(elem.tagName);
-debug(elem instanceof HTMLImageElement);
-debug(elem.width);
+var elem = document.documentElement.firstChild.firstChild.nextSibling.firstChild;
+window.alert(elem.tagName);
+window.alert(elem instanceof HTMLImageElement);
+window.alert(elem instanceof HTMLElement);
+window.alert(elem instanceof Element);
+window.alert(elem.width);
 setWidth(1000, -10);
\ No newline at end of file