--- a/content/events/src/nsDOMCommandEvent.cpp
+++ b/content/events/src/nsDOMCommandEvent.cpp
@@ -13,16 +13,17 @@ nsDOMCommandEvent::nsDOMCommandEvent(moz
                new nsCommandEvent(false, nullptr, nullptr, nullptr))
 {
   mEvent->time = PR_Now();
   if (aEvent) {
     mEventIsInternal = false;
   } else {
     mEventIsInternal = true;
   }
+  SetIsDOMBinding();
 }
 
 nsDOMCommandEvent::~nsDOMCommandEvent()
 {
   if (mEventIsInternal && mEvent->eventStructType == NS_COMMAND_EVENT) {
     delete static_cast<nsCommandEvent*>(mEvent);
     mEvent = nullptr;
   }

--- a/content/events/src/nsDOMCommandEvent.h
+++ b/content/events/src/nsDOMCommandEvent.h
@@ -3,27 +3,42 @@
  * 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/. */
 
 #ifndef nsDOMCommandEvent_h__
 #define nsDOMCommandEvent_h__
 
 #include "nsIDOMCommandEvent.h"
 #include "nsDOMEvent.h"
+#include "mozilla/dom/CommandEventBinding.h"
 
 class nsDOMCommandEvent : public nsDOMEvent,
                           public nsIDOMCommandEvent
 {
 public:
   nsDOMCommandEvent(mozilla::dom::EventTarget* aOwner,
                     nsPresContext* aPresContext,
                     nsCommandEvent* aEvent);
   virtual ~nsDOMCommandEvent();
 
   NS_DECL_ISUPPORTS_INHERITED
 
   NS_DECL_NSIDOMCOMMANDEVENT
 
   // Forward to base class
   NS_FORWARD_TO_NSDOMEVENT
+
+  virtual JSObject* WrapObject(JSContext* aCx, JSObject* aScope)
+  {
+    return mozilla::dom::CommandEventBinding::Wrap(aCx, aScope, this);
+  }
+
+  void InitCommandEvent(const nsAString& aType,
+                        bool aCanBubble,
+                        bool aCancelable,
+                        const nsAString& aCommand,
+                        mozilla::ErrorResult& aRv)
+  {
+    aRv = InitCommandEvent(aType, aCanBubble, aCancelable, aCommand);
+  }
 };
 
 #endif // nsDOMCommandEvent_h__

--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -154,16 +154,20 @@ DOMInterfaces = {
 },
 
 'ClientRectList': {
     'nativeType': 'nsClientRectList',
     'headerFile': 'nsClientRect.h',
     'resultNotAddRefed': [ 'item' ]
 },
 
+'CommandEvent': {
+    'nativeType': 'nsDOMCommandEvent',
+},
+
 'CSS': {
     'concrete': False,
 },
 
 'CSS2Properties': {
   'nativeType': 'nsDOMCSSDeclaration'
 },
 

new file mode 100644
--- /dev/null
+++ b/dom/webidl/CommandEvent.webidl
@@ -0,0 +1,14 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/.
+ */
+
+interface CommandEvent : Event {
+  readonly attribute DOMString? command;
+
+  void initCommandEvent(DOMString type,
+                        boolean canBubble,
+                        boolean cancelable,
+                        DOMString? command);
+};

--- a/dom/webidl/WebIDL.mk
+++ b/dom/webidl/WebIDL.mk
@@ -22,16 +22,17 @@ webidl_files = \
   BiquadFilterNode.webidl \
   Blob.webidl \
   CanvasRenderingContext2D.webidl \
   CaretPosition.webidl \
   CDATASection.webidl \
   CFStateChangeEvent.webidl \
   CharacterData.webidl \
   ClientRectList.webidl \
+  CommandEvent.webidl \
   Comment.webidl \
   CSS.webidl \
   CSSPrimitiveValue.webidl \
   CSSStyleDeclaration.webidl \
   CSSValue.webidl \
   CSSValueList.webidl \
   DelayNode.webidl \
   Document.webidl \