diff --git a/content/base/public/nsIContentList.h b/content/base/public/nsIContentList.h
index 17b4a7d96fe4..67d417147fd3 100644
--- a/content/base/public/nsIContentList.h
+++ b/content/base/public/nsIContentList.h
@@ -56,6 +56,11 @@ public:
 
   NS_DEFINE_STATIC_IID_ACCESSOR(NS_ICONTENTLIST_IID)
 
+  /**
+   * Returns the object that the content list should be parented to.
+   */
+  NS_IMETHOD GetParentObject(nsISupports** aParentObject) = 0;
+    
   // Callers will want to pass in PR_TRUE for aDoFlush unless they
   // are explicitly avoiding an FlushPendingNotifications.  The
   // flush guarantees that the list will be up to date.
diff --git a/content/base/src/nsContentList.cpp b/content/base/src/nsContentList.cpp
index 4c27d62175f3..711d1bd7ad1e 100644
--- a/content/base/src/nsContentList.cpp
+++ b/content/base/src/nsContentList.cpp
@@ -449,7 +449,7 @@ nsContentList::~nsContentList()
 NS_INTERFACE_MAP_BEGIN(nsContentList)
   NS_INTERFACE_MAP_ENTRY(nsIDOMHTMLCollection)
   NS_INTERFACE_MAP_ENTRY(nsIContentList)
-  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(HTMLCollection)
+  NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(ContentList)
 NS_INTERFACE_MAP_END_INHERITING(nsBaseContentList)
 
 
@@ -457,6 +457,19 @@ NS_IMPL_ADDREF_INHERITED(nsContentList, nsBaseContentList)
 NS_IMPL_RELEASE_INHERITED(nsContentList, nsBaseContentList)
 
 
+NS_IMETHODIMP
+nsContentList::GetParentObject(nsISupports** aParentObject)
+{
+  if (mRootContent) {
+    *aParentObject = mRootContent;
+  } else {
+    *aParentObject = mDocument;
+  }
+
+  NS_IF_ADDREF(*aParentObject);
+  return NS_OK;
+}
+  
 NS_IMETHODIMP 
 nsContentList::GetLength(PRUint32* aLength, PRBool aDoFlush)
 {
diff --git a/content/base/src/nsContentList.h b/content/base/src/nsContentList.h
index d6d6e37114f1..0a29880d60ac 100644
--- a/content/base/src/nsContentList.h
+++ b/content/base/src/nsContentList.h
@@ -171,6 +171,7 @@ public:
   NS_IMETHOD NamedItem(const nsAString& aName, nsIDOMNode** aReturn);
 
   /// nsIContentList
+  NS_IMETHOD GetParentObject(nsISupports** aParentObject);
   NS_IMETHOD GetLength(PRUint32* aLength, PRBool aDoFlush);
   NS_IMETHOD Item(PRUint32 aIndex, nsIDOMNode** aReturn,
                   PRBool aDoFlush);
diff --git a/dom/public/nsIDOMClassInfo.h b/dom/public/nsIDOMClassInfo.h
index 17ed04d66556..10b8291df015 100644
--- a/dom/public/nsIDOMClassInfo.h
+++ b/dom/public/nsIDOMClassInfo.h
@@ -254,8 +254,13 @@ enum nsDOMClassInfoID {
 
   eDOMClassInfo_RangeException_id,
 
+  // CSSValueList object that represents an nsIDOMCSSValueList, used
+  // by DOM CSS
   eDOMClassInfo_CSSValueList_id,
 
+  // ContentList object used for various live NodeLists
+  eDOMClassInfo_ContentList_id,
+  
   // This one better be the last one in this list
   eDOMClassInfoIDCount
 };
diff --git a/dom/src/base/nsDOMClassInfo.cpp b/dom/src/base/nsDOMClassInfo.cpp
index 81d60642291e..4b75a905f7d9 100644
--- a/dom/src/base/nsDOMClassInfo.cpp
+++ b/dom/src/base/nsDOMClassInfo.cpp
@@ -134,6 +134,9 @@
 #include "nsIDOMHTMLOptionElement.h"
 #include "nsIDOMNSHTMLOptionCollectn.h"
 
+// ContentList includes
+#include "nsIContentList.h"
+
 // Event related includes
 #include "nsIEventListenerManager.h"
 #include "nsIDOMEventReceiver.h"
@@ -792,6 +795,10 @@ static nsDOMClassInfoData sClassInfoData[] = {
   NS_DEFINE_CLASSINFO_DATA(CSSValueList, nsCSSValueListSH,
                            ARRAY_SCRIPTABLE_FLAGS)
 
+  NS_DEFINE_CLASSINFO_DATA_WITH_NAME(ContentList, HTMLCollection,
+                                     nsContentListSH,
+                                     ARRAY_SCRIPTABLE_FLAGS |
+                                     nsIXPCScriptable::WANT_PRECREATE)
 };
 
 nsIXPConnect *nsDOMClassInfo::sXPConnect = nsnull;
@@ -2093,6 +2100,11 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIException)
   DOM_CLASSINFO_MAP_END
 
+  DOM_CLASSINFO_MAP_BEGIN(ContentList, nsIDOMHTMLCollection)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMNodeList)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMHTMLCollection)
+  DOM_CLASSINFO_MAP_END
+
 #ifdef NS_DEBUG
   {
     PRUint32 i = sizeof(sClassInfoData) / sizeof(sClassInfoData[0]);
@@ -4468,7 +4480,32 @@ nsHTMLCollectionSH::GetNamedItem(nsISupports *aNative,
 }
 
 
-// FomrControlList helper
+// ContentList helper
+nsresult
+nsContentListSH::PreCreate(nsISupports *nativeObj, JSContext *cx,
+                           JSObject *globalObj, JSObject **parentObj)
+{
+  nsCOMPtr<nsIContentList> contentList(do_QueryInterface(nativeObj));
+  NS_ASSERTION(contentList, "Why does something not implementing nsIContentList use nsContentListSH??");
+
+  nsCOMPtr<nsISupports> native_parent;
+  contentList->GetParentObject(getter_AddRefs(native_parent));
+
+  if (!native_parent) {
+    *parentObj = globalObj;
+    return NS_OK;
+  }
+
+  jsval v;
+  nsresult rv = WrapNative(cx, ::JS_GetGlobalObject(cx), native_parent,
+                           NS_GET_IID(nsISupports), &v);
+
+  *parentObj = JSVAL_TO_OBJECT(v);
+    
+  return rv;
+}
+
+// FormControlList helper
 
 nsresult
 nsFormControlListSH::GetNamedItem(nsISupports *aNative,
diff --git a/dom/src/base/nsDOMClassInfo.h b/dom/src/base/nsDOMClassInfo.h
index 2082cd91d995..2b33816abedc 100644
--- a/dom/src/base/nsDOMClassInfo.h
+++ b/dom/src/base/nsDOMClassInfo.h
@@ -524,6 +524,31 @@ public:
 };
 
 
+// ContentList helper
+
+class nsContentListSH : public nsHTMLCollectionSH
+{
+protected:
+  nsContentListSH(nsDOMClassInfoData* aData) : nsHTMLCollectionSH(aData)
+  {
+  }
+
+  virtual ~nsContentListSH()
+  {
+  }
+
+public:
+  NS_IMETHOD PreCreate(nsISupports *nativeObj, JSContext *cx,
+                       JSObject *globalObj, JSObject **parentObj);
+
+  static nsIClassInfo *doCreate(nsDOMClassInfoData* aData)
+  {
+    return new nsContentListSH(aData);
+  }
+};
+
+
+
 // FomrControlList helper
 
 class nsFormControlListSH : public nsHTMLCollectionSH