diff --git a/content/html/content/src/HTMLHeadingElement.h b/content/html/content/src/HTMLHeadingElement.h
index 98eba583df9..e26ed5c2290 100644
--- a/content/html/content/src/HTMLHeadingElement.h
+++ b/content/html/content/src/HTMLHeadingElement.h
@@ -48,6 +48,9 @@ public:
   virtual nsXPCClassInfo* GetClassInfo();
   virtual nsIDOMNode* AsDOMNode() { return this; }
 
+  // The XPCOM versions of GetAlign and SetAlign are fine for us for
+  // use from WebIDL.
+
 protected:
   virtual JSObject* WrapNode(JSContext *aCx, JSObject *aScope,
                              bool *aTriedToWrap) MOZ_OVERRIDE;
diff --git a/dom/webidl/HTMLHeadingElement.webidl b/dom/webidl/HTMLHeadingElement.webidl
index 4c78e252ebc..2f13880f00e 100644
--- a/dom/webidl/HTMLHeadingElement.webidl
+++ b/dom/webidl/HTMLHeadingElement.webidl
@@ -4,11 +4,19 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  *
  * The origin of this IDL file is
- * http://www.whatwg.org/specs/web-apps/current-work/
- *
+ * http://www.whatwg.org/specs/web-apps/current-work/#the-h1,-h2,-h3,-h4,-h5,-and-h6-elements
+ * http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
  * © Copyright 2004-2011 Apple Computer, Inc., Mozilla Foundation, and
  * Opera Software ASA. You are granted a license to use, reproduce
  * and create derivative works of this document.
  */
 
-interface HTMLHeadingElement : HTMLElement {};
+// http://www.whatwg.org/specs/web-apps/current-work/#the-h1,-h2,-h3,-h4,-h5,-and-h6-elements
+interface HTMLHeadingElement : HTMLElement {
+/*};
+
+// http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
+partial interface HTMLHeadingElement {
+*/
+           attribute DOMString align;
+};