diff --git a/src/components/script/dom/webidls/Window.webidl b/src/components/script/dom/webidls/Window.webidl
index 772b0f76f82..ad18ff9998e 100644
--- a/src/components/script/dom/webidls/Window.webidl
+++ b/src/components/script/dom/webidls/Window.webidl
@@ -84,3 +84,9 @@ interface WindowTimers {
   void clearInterval(optional long handle = 0);*/
 };
 Window implements WindowTimers;
+
+// Proprietary extensions.
+partial interface Window {
+  void debug(DOMString arg);
+  void gc();
+};
diff --git a/src/components/script/dom/window.rs b/src/components/script/dom/window.rs
index 2af5f174430..ab51a5f457c 100644
--- a/src/components/script/dom/window.rs
+++ b/src/components/script/dom/window.rs
@@ -23,6 +23,7 @@ use servo_util::str::DOMString;
 use servo_util::task::{spawn_named};
 
 use js::jsapi::JSContext;
+use js::jsapi::{JS_GC, JS_GetRuntime};
 use js::jsval::{NullValue, JSVal};
 
 use collections::hashmap::HashMap;
@@ -138,6 +139,8 @@ pub trait WindowMethods {
     fn Window(&self) -> Temporary<Window>;
     fn Self(&self) -> Temporary<Window>;
     fn Performance(&mut self) -> Temporary<Performance>;
+    fn Debug(&self, message: DOMString);
+    fn Gc(&self);
 }
 
 impl<'a> WindowMethods for JSRef<'a, Window> {
@@ -263,6 +266,16 @@ impl<'a> WindowMethods for JSRef<'a, Window> {
         }
         Temporary::new(self.performance.get_ref().clone())
     }
+
+    fn Debug(&self, message: DOMString) {
+        debug!("{:s}", message);
+    }
+
+    fn Gc(&self) {
+        unsafe {
+            JS_GC(JS_GetRuntime(self.get_cx()));
+        }
+    }
 }
 
 impl Reflectable for Window {
diff --git a/src/components/script/script_task.rs b/src/components/script/script_task.rs
index 45f1349b3f6..3016edad524 100644
--- a/src/components/script/script_task.rs
+++ b/src/components/script/script_task.rs
@@ -34,8 +34,7 @@ use layout_interface;
 
 use geom::point::Point2D;
 use geom::size::Size2D;
-use js::global::DEBUG_FNS;
-use js::jsapi::{JS_CallFunctionValue, JS_DefineFunctions};
+use js::jsapi::JS_CallFunctionValue;
 use js::jsapi::{JS_SetWrapObjectCallbacks, JS_SetGCZeal, JS_DEFAULT_ZEAL_FREQ, JS_GC};
 use js::jsapi::{JSContext, JSRuntime};
 use js::jsval::NullValue;
@@ -1004,13 +1003,6 @@ impl ScriptTask {
         debug!("js_scripts: {:?}", js_scripts);
 
         with_compartment((**cx).ptr, window.reflector().get_jsobject(), || {
-            // Define debug functions.
-            unsafe {
-                assert!(JS_DefineFunctions((**cx).ptr,
-                                           window.reflector().get_jsobject(),
-                                           DEBUG_FNS.as_ptr()) != 0);
-            }
-
             // Evaluate every script in the document.
             for file in js_scripts.iter() {
                 let global_obj = window.reflector().get_jsobject();
diff --git a/src/support/spidermonkey/rust-mozjs b/src/support/spidermonkey/rust-mozjs
index 50365a556b5..07acb44df9b 160000
--- a/src/support/spidermonkey/rust-mozjs
+++ b/src/support/spidermonkey/rust-mozjs
@@ -1 +1 @@
-Subproject commit 50365a556b51da2455de051bfe4697872f49d8df
+Subproject commit 07acb44df9b3f638743931f392c0ebe7040a7bab