diff --git a/dom/broadcastchannel/BroadcastChannel.cpp b/dom/broadcastchannel/BroadcastChannel.cpp
index 753377f015aa..a37e342e4519 100644
--- a/dom/broadcastchannel/BroadcastChannel.cpp
+++ b/dom/broadcastchannel/BroadcastChannel.cpp
@@ -7,6 +7,7 @@
 #include "BroadcastChannelChild.h"
 #include "mozilla/dom/BroadcastChannelBinding.h"
 #include "mozilla/dom/Navigator.h"
+#include "mozilla/dom/StructuredCloneUtils.h"
 #include "mozilla/ipc/BackgroundChild.h"
 #include "mozilla/ipc/BackgroundUtils.h"
 #include "mozilla/ipc/PBackgroundChild.h"
@@ -28,6 +29,22 @@ namespace dom {
 
 using namespace workers;
 
+class BroadcastChannelMessage MOZ_FINAL
+{
+public:
+  NS_INLINE_DECL_REFCOUNTING(BroadcastChannelMessage)
+
+  JSAutoStructuredCloneBuffer mBuffer;
+  StructuredCloneClosure mClosure;
+
+  BroadcastChannelMessage()
+  { }
+
+private:
+  ~BroadcastChannelMessage()
+  { }
+};
+
 namespace {
 
 void
@@ -159,9 +176,9 @@ public:
   NS_DECL_ISUPPORTS
 
   PostMessageRunnable(BroadcastChannelChild* aActor,
-                      const nsAString& aMessage)
+                      BroadcastChannelMessage* aData)
     : mActor(aActor)
-    , mMessage(aMessage)
+    , mData(aData)
   {
     MOZ_ASSERT(mActor);
   }
@@ -169,9 +186,24 @@ public:
   NS_IMETHODIMP Run()
   {
     MOZ_ASSERT(mActor);
-    if (!mActor->IsActorDestroyed()) {
-      mActor->SendPostMessage(mMessage);
+    if (mActor->IsActorDestroyed()) {
+      return NS_OK;
     }
+
+    BroadcastChannelMessageData message;
+
+    SerializedStructuredCloneBuffer& buffer = message.data();
+    buffer.data = mData->mBuffer.data();
+    buffer.dataLength = mData->mBuffer.nbytes();
+
+#ifdef DEBUG
+    {
+      const nsTArray<nsRefPtr<File>>& blobs = mData->mClosure.mBlobs;
+      MOZ_ASSERT(blobs.IsEmpty());
+    }
+#endif
+
+    mActor->SendPostMessage(message);
     return NS_OK;
   }
 
@@ -185,7 +217,7 @@ private:
   ~PostMessageRunnable() {}
 
   nsRefPtr<BroadcastChannelChild> mActor;
-  nsString mMessage;
+  nsRefPtr<BroadcastChannelMessage> mData;
 };
 
 NS_IMPL_ISUPPORTS(PostMessageRunnable, nsICancelableRunnable, nsIRunnable)
@@ -460,22 +492,38 @@ BroadcastChannel::Constructor(const GlobalObject& aGlobal,
 }
 
 void
-BroadcastChannel::PostMessage(const nsAString& aMessage, ErrorResult& aRv)
+BroadcastChannel::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+                              ErrorResult& aRv)
 {
   if (mState != StateActive) {
     aRv.Throw(NS_ERROR_FAILURE);
     return;
   }
 
-  PostMessageInternal(aMessage);
+  PostMessageInternal(aCx, aMessage, aRv);
 }
 
 void
-BroadcastChannel::PostMessageInternal(const nsAString& aMessage)
+BroadcastChannel::PostMessageInternal(JSContext* aCx,
+                                      JS::Handle<JS::Value> aMessage,
+                                      ErrorResult& aRv)
+{
+  nsRefPtr<BroadcastChannelMessage> data = new BroadcastChannelMessage();
+
+  if (!WriteStructuredClone(aCx, aMessage, data->mBuffer, data->mClosure)) {
+    aRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
+    return;
+  }
+
+  PostMessageData(data);
+}
+
+void
+BroadcastChannel::PostMessageData(BroadcastChannelMessage* aData)
 {
   if (mActor) {
     nsRefPtr<PostMessageRunnable> runnable =
-      new PostMessageRunnable(mActor, aMessage);
+      new PostMessageRunnable(mActor, aData);
 
     if (NS_FAILED(NS_DispatchToCurrentThread(runnable))) {
       NS_WARNING("Failed to dispatch to the current thread!");
@@ -484,7 +532,7 @@ BroadcastChannel::PostMessageInternal(const nsAString& aMessage)
     return;
   }
 
-  mPendingMessages.AppendElement(aMessage);
+  mPendingMessages.AppendElement(aData);
 }
 
 void
@@ -527,7 +575,7 @@ BroadcastChannel::ActorCreated(ipc::PBackgroundChild* aActor)
 
   // Flush pending messages.
   for (uint32_t i = 0; i < mPendingMessages.Length(); ++i) {
-    PostMessageInternal(mPendingMessages[i]);
+    PostMessageData(mPendingMessages[i]);
   }
 
   mPendingMessages.Clear();
diff --git a/dom/broadcastchannel/BroadcastChannel.h b/dom/broadcastchannel/BroadcastChannel.h
index ec959a5db0f2..f268882e512d 100644
--- a/dom/broadcastchannel/BroadcastChannel.h
+++ b/dom/broadcastchannel/BroadcastChannel.h
@@ -24,6 +24,7 @@ class WorkerFeature;
 }
 
 class BroadcastChannelChild;
+struct BroadcastChannelMessage;
 
 class BroadcastChannel MOZ_FINAL
   : public DOMEventTargetHelper
@@ -55,7 +56,8 @@ public:
     aName = mChannel;
   }
 
-  void PostMessage(const nsAString& aMessage, ErrorResult& aRv);
+  void PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+                   ErrorResult& aRv);
 
   void Close();
 
@@ -85,12 +87,15 @@ private:
 
   ~BroadcastChannel();
 
-  void PostMessageInternal(const nsAString& aMessage);
+  void PostMessageData(BroadcastChannelMessage* aData);
+
+  void PostMessageInternal(JSContext* aCx, JS::Handle<JS::Value> aMessage,
+                           ErrorResult& aRv);
 
   void UpdateMustKeepAlive();
 
   nsRefPtr<BroadcastChannelChild> mActor;
-  nsTArray<nsString> mPendingMessages;
+  nsTArray<nsRefPtr<BroadcastChannelMessage>> mPendingMessages;
 
   workers::WorkerFeature* mWorkerFeature;
 
diff --git a/dom/broadcastchannel/BroadcastChannelChild.cpp b/dom/broadcastchannel/BroadcastChannelChild.cpp
index b420a3c6c178..462e1fb82dfa 100644
--- a/dom/broadcastchannel/BroadcastChannelChild.cpp
+++ b/dom/broadcastchannel/BroadcastChannelChild.cpp
@@ -8,6 +8,9 @@
 #include "jsapi.h"
 #include "mozilla/dom/MessageEvent.h"
 #include "mozilla/dom/MessageEventBinding.h"
+#include "mozilla/dom/StructuredCloneUtils.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WorkerScope.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/ipc/PBackgroundChild.h"
 #include "WorkerPrivate.h"
@@ -34,7 +37,7 @@ BroadcastChannelChild::~BroadcastChannelChild()
 }
 
 bool
-BroadcastChannelChild::RecvNotify(const nsString& aMessage)
+BroadcastChannelChild::RecvNotify(const BroadcastChannelMessageData& aData)
 {
   nsCOMPtr<DOMEventTargetHelper> helper = mBC;
   nsCOMPtr<EventTarget> eventTarget = do_QueryInterface(helper);
@@ -50,39 +53,36 @@ BroadcastChannelChild::RecvNotify(const nsString& aMessage)
     return true;
   }
 
-  if (NS_IsMainThread()) {
-    AutoJSAPI autoJS;
-    if (!autoJS.Init(mBC->GetParentObject())) {
-      NS_WARNING("Dropping message");
-      return true;
-    }
+  AutoJSAPI jsapi;
+  nsCOMPtr<nsIGlobalObject> globalObject;
 
-    Notify(autoJS.cx(), aMessage);
+  if (NS_IsMainThread()) {
+    globalObject = do_QueryInterface(mBC->GetParentObject());
+  } else {
+    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
+    MOZ_ASSERT(workerPrivate);
+    globalObject = workerPrivate->GlobalScope();
+  }
+
+  if (!globalObject || !jsapi.Init(globalObject)) {
+    NS_WARNING("Failed to initialize AutoJSAPI object.");
     return true;
   }
 
-  WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
-  MOZ_ASSERT(workerPrivate);
+  JSContext* cx = jsapi.cx();
 
-  Notify(workerPrivate->GetJSContext(), aMessage);
-  return true;
-}
+  const SerializedStructuredCloneBuffer& buffer = aData.data();
+  StructuredCloneData cloneData;
+  cloneData.mData = buffer.data;
+  cloneData.mDataLength = buffer.dataLength;
 
-void
-BroadcastChannelChild::Notify(JSContext* aCx, const nsString& aMessage)
-{
-  JS::Rooted<JSString*> str(aCx,
-                            JS_NewUCStringCopyN(aCx, aMessage.get(),
-                                                aMessage.Length()));
-  if (!str) {
-    // OOM, no exception needed.
-    NS_WARNING("Failed allocating a JS string. Probably OOM.");
-    return;
+  JS::Rooted<JS::Value> value(cx, JS::NullValue());
+  if (cloneData.mDataLength && !ReadStructuredClone(cx, cloneData, &value)) {
+    JS_ClearPendingException(cx);
+    return false;
   }
 
-  JS::Rooted<JS::Value> value(aCx, JS::StringValue(str));
-
-  RootedDictionary<MessageEventInit> init(aCx);
+  RootedDictionary<MessageEventInit> init(cx);
   init.mBubbles = false;
   init.mCancelable = false;
   init.mOrigin.Construct(mOrigin);
@@ -93,13 +93,15 @@ BroadcastChannelChild::Notify(JSContext* aCx, const nsString& aMessage)
     MessageEvent::Constructor(mBC, NS_LITERAL_STRING("message"), init, rv);
   if (rv.Failed()) {
     NS_WARNING("Failed to create a MessageEvent object.");
-    return;
+    return true;
   }
 
   event->SetTrusted(true);
 
   bool status;
   mBC->DispatchEvent(static_cast<Event*>(event.get()), &status);
+
+  return true;
 }
 
 void
diff --git a/dom/broadcastchannel/BroadcastChannelChild.h b/dom/broadcastchannel/BroadcastChannelChild.h
index 7a3329e763d8..26ab6886043d 100644
--- a/dom/broadcastchannel/BroadcastChannelChild.h
+++ b/dom/broadcastchannel/BroadcastChannelChild.h
@@ -29,7 +29,8 @@ public:
     mBC = aBC;
   }
 
-  virtual bool RecvNotify(const nsString& aMessage) MOZ_OVERRIDE;
+  virtual bool RecvNotify(const BroadcastChannelMessageData& aData)
+                                                                   MOZ_OVERRIDE;
 
   bool IsActorDestroyed() const
   {
@@ -42,8 +43,6 @@ private:
 
   ~BroadcastChannelChild();
 
-  void Notify(JSContext* aCx, const nsString& aMessage);
-
   void ActorDestroy(ActorDestroyReason aWhy);
 
   // This raw pointer is actually the parent object.
diff --git a/dom/broadcastchannel/BroadcastChannelParent.cpp b/dom/broadcastchannel/BroadcastChannelParent.cpp
index 79794aad5bf3..83b360a7a1d9 100644
--- a/dom/broadcastchannel/BroadcastChannelParent.cpp
+++ b/dom/broadcastchannel/BroadcastChannelParent.cpp
@@ -31,7 +31,8 @@ BroadcastChannelParent::~BroadcastChannelParent()
 }
 
 bool
-BroadcastChannelParent::RecvPostMessage(const nsString& aMessage)
+BroadcastChannelParent::RecvPostMessage(
+                                       const BroadcastChannelMessageData& aData)
 {
   AssertIsOnBackgroundThread();
 
@@ -39,7 +40,7 @@ BroadcastChannelParent::RecvPostMessage(const nsString& aMessage)
     return false;
   }
 
-  mService->PostMessage(this, aMessage, mOrigin, mChannel);
+  mService->PostMessage(this, aData, mOrigin, mChannel);
   return true;
 }
 
@@ -73,14 +74,15 @@ BroadcastChannelParent::ActorDestroy(ActorDestroyReason aWhy)
 }
 
 void
-BroadcastChannelParent::CheckAndDeliver(const nsString& aMessage,
-                                        const nsString& aOrigin,
-                                        const nsString& aChannel)
+BroadcastChannelParent::CheckAndDeliver(
+                                       const BroadcastChannelMessageData& aData,
+                                       const nsString& aOrigin,
+                                       const nsString& aChannel)
 {
   AssertIsOnBackgroundThread();
 
   if (aOrigin == mOrigin && aChannel == mChannel) {
-    unused << SendNotify(aMessage);
+    unused << SendNotify(aData);
   }
 }
 
diff --git a/dom/broadcastchannel/BroadcastChannelParent.h b/dom/broadcastchannel/BroadcastChannelParent.h
index de6be5adead0..752d34612e2c 100644
--- a/dom/broadcastchannel/BroadcastChannelParent.h
+++ b/dom/broadcastchannel/BroadcastChannelParent.h
@@ -22,7 +22,7 @@ class BroadcastChannelParent MOZ_FINAL : public PBroadcastChannelParent
   friend class mozilla::ipc::BackgroundParentImpl;
 
 public:
-  void CheckAndDeliver(const nsString& aMessage,
+  void CheckAndDeliver(const BroadcastChannelMessageData& aData,
                        const nsString& aOrigin,
                        const nsString& aChannel);
 
@@ -31,7 +31,8 @@ private:
                          const nsAString& aChannel);
   ~BroadcastChannelParent();
 
-  virtual bool RecvPostMessage(const nsString& aMessage) MOZ_OVERRIDE;
+  virtual bool
+  RecvPostMessage(const BroadcastChannelMessageData& aData) MOZ_OVERRIDE;
 
   virtual bool RecvClose() MOZ_OVERRIDE;
 
diff --git a/dom/broadcastchannel/BroadcastChannelService.cpp b/dom/broadcastchannel/BroadcastChannelService.cpp
index e1045e333dc0..e215d36aa0d5 100644
--- a/dom/broadcastchannel/BroadcastChannelService.cpp
+++ b/dom/broadcastchannel/BroadcastChannelService.cpp
@@ -75,11 +75,11 @@ namespace {
 struct MOZ_STACK_CLASS PostMessageData MOZ_FINAL
 {
   PostMessageData(BroadcastChannelParent* aParent,
-                  const nsAString& aMessage,
+                  const BroadcastChannelMessageData& aData,
                   const nsAString& aOrigin,
                   const nsAString& aChannel)
     : mParent(aParent)
-    , mMessage(aMessage)
+    , mData(aData)
     , mOrigin(aOrigin)
     , mChannel(aChannel)
   {
@@ -93,7 +93,7 @@ struct MOZ_STACK_CLASS PostMessageData MOZ_FINAL
   }
 
   BroadcastChannelParent* mParent;
-  const nsString mMessage;
+  const BroadcastChannelMessageData& mData;
   const nsString mOrigin;
   const nsString mChannel;
 };
@@ -108,7 +108,7 @@ PostMessageEnumerator(nsPtrHashKey<BroadcastChannelParent>* aKey, void* aPtr)
   MOZ_ASSERT(parent);
 
   if (parent != data->mParent) {
-    parent->CheckAndDeliver(data->mMessage, data->mOrigin, data->mChannel);
+    parent->CheckAndDeliver(data->mData, data->mOrigin, data->mChannel);
   }
 
   return PL_DHASH_NEXT;
@@ -118,7 +118,7 @@ PostMessageEnumerator(nsPtrHashKey<BroadcastChannelParent>* aKey, void* aPtr)
 
 void
 BroadcastChannelService::PostMessage(BroadcastChannelParent* aParent,
-                                     const nsAString& aMessage,
+                                     const BroadcastChannelMessageData& aData,
                                      const nsAString& aOrigin,
                                      const nsAString& aChannel)
 {
@@ -126,7 +126,7 @@ BroadcastChannelService::PostMessage(BroadcastChannelParent* aParent,
   MOZ_ASSERT(aParent);
   MOZ_ASSERT(mAgents.Contains(aParent));
 
-  PostMessageData data(aParent, aMessage, aOrigin, aChannel);
+  PostMessageData data(aParent, aData, aOrigin, aChannel);
   mAgents.EnumerateEntries(PostMessageEnumerator, &data);
 }
 
diff --git a/dom/broadcastchannel/BroadcastChannelService.h b/dom/broadcastchannel/BroadcastChannelService.h
index 338cd51f57e1..83341d81aa92 100644
--- a/dom/broadcastchannel/BroadcastChannelService.h
+++ b/dom/broadcastchannel/BroadcastChannelService.h
@@ -13,6 +13,7 @@ namespace mozilla {
 namespace dom {
 
 class BroadcastChannelParent;
+class BroadcastChannelMessageData;
 
 class BroadcastChannelService MOZ_FINAL
 {
@@ -25,7 +26,7 @@ public:
   void UnregisterActor(BroadcastChannelParent* aParent);
 
   void PostMessage(BroadcastChannelParent* aParent,
-                   const nsAString& aMessage,
+                   const BroadcastChannelMessageData& aData,
                    const nsAString& aOrigin,
                    const nsAString& aChannel);
 
diff --git a/dom/broadcastchannel/PBroadcastChannel.ipdl b/dom/broadcastchannel/PBroadcastChannel.ipdl
index 62a5307fac06..8115283f94ef 100644
--- a/dom/broadcastchannel/PBroadcastChannel.ipdl
+++ b/dom/broadcastchannel/PBroadcastChannel.ipdl
@@ -4,20 +4,27 @@
 
 include protocol PBackground;
 
+using struct mozilla::SerializedStructuredCloneBuffer from "ipc/IPCMessageUtils.h";
+
 namespace mozilla {
 namespace dom {
 
+struct BroadcastChannelMessageData
+{
+  SerializedStructuredCloneBuffer data;
+};
+
 // This protocol is used for the BroadcastChannel API
 protocol PBroadcastChannel
 {
   manager PBackground;
 
 parent:
-  PostMessage(nsString message);
+  PostMessage(BroadcastChannelMessageData message);
   Close();
 
 child:
-  Notify(nsString message);
+  Notify(BroadcastChannelMessageData message);
   __delete__();
 };
 
diff --git a/dom/broadcastchannel/tests/broadcastchannel_worker.js b/dom/broadcastchannel/tests/broadcastchannel_worker.js
index 30d27e83ac19..4714d59d0216 100644
--- a/dom/broadcastchannel/tests/broadcastchannel_worker.js
+++ b/dom/broadcastchannel/tests/broadcastchannel_worker.js
@@ -10,8 +10,7 @@ onmessage = function(evt) {
 
   var bc = new BroadcastChannel('foobar');
   bc.addEventListener('message', function(event) {
-    postMessage(event.data == "hello world from the window" ? "OK" : "KO");
-    bc.postMessage("hello world from the worker");
+    bc.postMessage(event.data == "hello world from the window" ? "hello world from the worker" : "KO");
     bc.close();
   }, false);
 
diff --git a/dom/broadcastchannel/tests/broadcastchannel_worker_any.js b/dom/broadcastchannel/tests/broadcastchannel_worker_any.js
new file mode 100644
index 000000000000..da8625c4d8e9
--- /dev/null
+++ b/dom/broadcastchannel/tests/broadcastchannel_worker_any.js
@@ -0,0 +1,5 @@
+(new BroadcastChannel('foobar')).onmessage = function(event) {
+  event.target.postMessage(event.data);
+}
+
+postMessage("READY");
diff --git a/dom/broadcastchannel/tests/mochitest.ini b/dom/broadcastchannel/tests/mochitest.ini
index 63ad9725adc2..ab8869a45367 100644
--- a/dom/broadcastchannel/tests/mochitest.ini
+++ b/dom/broadcastchannel/tests/mochitest.ini
@@ -5,7 +5,9 @@ support-files =
   broadcastchannel_sharedWorker.js
   broadcastchannel_worker.js
   broadcastchannel_worker_alive.js
+  broadcastchannel_worker_any.js
 
+[test_broadcastchannel_any.html]
 [test_broadcastchannel_basic.html]
 [test_broadcastchannel_close.html]
 [test_broadcastchannel_self.html]
diff --git a/dom/broadcastchannel/tests/test_broadcastchannel_any.html b/dom/broadcastchannel/tests/test_broadcastchannel_any.html
new file mode 100644
index 000000000000..748f321ac371
--- /dev/null
+++ b/dom/broadcastchannel/tests/test_broadcastchannel_any.html
@@ -0,0 +1,109 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test for BroadcastChannel</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+
+<div id="content"></div>
+
+<script type="application/javascript">
+
+var tests = [
+ 'hello world',
+ 123,
+ null,
+ true,
+ new Date(),
+ [ 1, 'test', true, new Date() ],
+ { a: true, b:  null, c: new Date(), d: [ true, false, {} ] },
+];
+
+var currentTest = null;
+
+function getType(a) {
+  if (a === null || a === undefined)
+    return 'null';
+
+  if (Array.isArray(a))
+    return 'array';
+
+  if (typeof a == 'object')
+    return 'object';
+
+  return 'primitive';
+}
+
+function compare(a, b) {
+  is (getType(a), getType(b), 'Type matches');
+
+  var type = getType(a);
+  if (type == 'array') {
+    is (a.length, b.length, 'Array.length matches');
+    for (var i = 0; i < a.length; ++i) {
+      compare(a[i], b[i]);
+    }
+
+    return;
+  }
+
+  if (type == 'object') {
+    ok (a !== b, 'They should not match');
+
+    var aProps = [];
+    for (var p in a) aProps.push(p);
+
+    var bProps = [];
+    for (var p in b) bProps.push(p);
+
+    is (aProps.length, bProps.length, 'Props match');
+    is (aProps.sort().toSource(), bProps.sort().toSource(), 'Props match - using toSource()');
+
+    for (var p in a) {
+      compare(a[p], b[p]);
+    }
+
+    return;
+  }
+
+  if (type != 'null') {
+    is (a.toSource(), b.toSource(), 'Matching using toSource()');
+  }
+}
+
+function runTest() {
+  var bc = new BroadcastChannel("foobar");
+  ok(bc, "BroadcastChannel can be created");
+
+  bc.onmessage = function(event) {
+    compare(event.data, currentTest);
+    next();
+  }
+
+  function next() {
+    if (!tests.length) {
+      SimpleTest.finish();
+      return;
+    }
+
+    currentTest = tests.shift();
+    bc.postMessage(currentTest);
+  }
+
+  var worker = new Worker("broadcastchannel_worker_any.js");
+  worker.onmessage = function(event) {
+    if (event.data == "READY") {
+      next();
+    }
+  };
+}
+
+SimpleTest.waitForExplicitFinish();
+SpecialPowers.pushPrefEnv({"set": [["dom.broadcastChannel.enabled", true]]}, runTest);
+
+</script>
+</body>
+</html>
+
diff --git a/dom/broadcastchannel/tests/test_broadcastchannel_worker.html b/dom/broadcastchannel/tests/test_broadcastchannel_worker.html
index 748d2c840e3b..6f731eb7a0fb 100644
--- a/dom/broadcastchannel/tests/test_broadcastchannel_worker.html
+++ b/dom/broadcastchannel/tests/test_broadcastchannel_worker.html
@@ -29,8 +29,6 @@ function testWorker(x) {
     if (event.data == "READY") {
       ok(true, "Worker is ready!");
       bc.postMessage('hello world from the window');
-    } else if(event.data == "OK") {
-      ok(true, "Worker has received the message");
     } else {
       ok(false, "Something wrong happened");
     }
diff --git a/dom/broadcastchannel/tests/test_broadcastchannel_worker_alive.html b/dom/broadcastchannel/tests/test_broadcastchannel_worker_alive.html
index 7fa358819cd2..340431b3cef0 100644
--- a/dom/broadcastchannel/tests/test_broadcastchannel_worker_alive.html
+++ b/dom/broadcastchannel/tests/test_broadcastchannel_worker_alive.html
@@ -28,7 +28,7 @@ function runTests() {
     if (event.data == "READY") {
       ok(true, "Worker is ready!");
     } else {
-      is(id, event.data, "The message is correct");
+      is(id, event.data, "The message is correct: " + id);
     }
 
     for (var i = 0; i < 3; ++i) {
@@ -38,6 +38,7 @@ function runTests() {
 
     if (id == 5) {
       SimpleTest.finish();
+      return;
     }
 
     event.target.postMessage(++id);
diff --git a/dom/webidl/BroadcastChannel.webidl b/dom/webidl/BroadcastChannel.webidl
index 1d0934ea835d..37c531d4a700 100644
--- a/dom/webidl/BroadcastChannel.webidl
+++ b/dom/webidl/BroadcastChannel.webidl
@@ -14,7 +14,7 @@ interface BroadcastChannel : EventTarget {
   readonly attribute DOMString name;
 
   [Throws]
-  void postMessage(DOMString message);
+  void postMessage(any message);
 
   void close();