diff --git a/dom/workers/ScriptLoader.cpp b/dom/workers/ScriptLoader.cpp
index 53474bded53b..321b602622ea 100644
--- a/dom/workers/ScriptLoader.cpp
+++ b/dom/workers/ScriptLoader.cpp
@@ -1879,9 +1879,8 @@ ScriptExecutorRunnable::ShutdownScriptLoader(JSContext* aCx,
     // 1) mScriptLoader.mRv.Failed().  In that case we just want to leave it
     //    as-is, except if it has a JS exception and we need to mute JS
     //    exceptions.  In that case, we log the exception without firing any
-    //    events and then replace it on the ErrorResult with a generic
-    //    NS_ERROR_FAILURE for lack of anything better.  XXXbz: This should
-    //    throw a NetworkError per spec updates.  See bug 1249673.
+    //    events and then replace it on the ErrorResult with a NetworkError,
+    //    per spec.
     //
     // 2) mScriptLoader.mRv succeeded.  As far as I can tell, this can only
     //    happen when loading the main worker script and
@@ -1891,7 +1890,7 @@ ScriptExecutorRunnable::ShutdownScriptLoader(JSContext* aCx,
     if (mScriptLoader.mRv.Failed()) {
       if (aMutedError && mScriptLoader.mRv.IsJSException()) {
         LogExceptionToConsole(aCx, aWorkerPrivate);
-        mScriptLoader.mRv.Throw(NS_ERROR_FAILURE);
+        mScriptLoader.mRv.Throw(NS_ERROR_DOM_NETWORK_ERR);
       }
     } else {
       mScriptLoader.mRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
diff --git a/dom/workers/test/importScripts_3rdParty_worker.js b/dom/workers/test/importScripts_3rdParty_worker.js
index 11c438db8fe6..ebf2d3b1497a 100644
--- a/dom/workers/test/importScripts_3rdParty_worker.js
+++ b/dom/workers/test/importScripts_3rdParty_worker.js
@@ -29,12 +29,12 @@ onmessage = function(a) {
   var fileName2 = 42;
 
   if (a.data.test == 'none') {
-    importScripts([crossOriginURL.href]);
+    importScripts(crossOriginURL.href);
     return;
   }
 
   try {
-    importScripts([sameOriginURL.href]);
+    importScripts(sameOriginURL.href);
   } catch(e) {
     if (!(e instanceof SyntaxError)) {
       postMessage({ result: false });
@@ -50,13 +50,17 @@ onmessage = function(a) {
   }
 
   if (a.data.test == 'try') {
+    var exception;
     try {
-      importScripts([crossOriginURL.href]);
+      importScripts(crossOriginURL.href);
     } catch(e) {
       fileName2 = e.filename;
+      exception = e;
     }
 
-    postMessage({ result: fileName2 == workerURL });
+    postMessage({ result: fileName2 == workerURL &&
+                          exception.name == "NetworkError" &&
+                          exception.code == DOMException.NETWORK_ERR });
     return;
   }
 
@@ -74,5 +78,5 @@ onmessage = function(a) {
     }
   }
 
-  importScripts([crossOriginURL.href]);
+  importScripts(crossOriginURL.href);
 }