diff --git a/dom/tests/mochitest/bugs/test_bug585240.html b/dom/tests/mochitest/bugs/test_bug585240.html
new file mode 100644
index 000000000000..20dcd41f9248
--- /dev/null
+++ b/dom/tests/mochitest/bugs/test_bug585240.html
@@ -0,0 +1,34 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=585240
+-->
+<head>
+  <title>Test for Bug 585240</title>
+  <script type="application/javascript" src="/MochiKit/packed.js"></script>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=585240">Mozilla Bug 585240</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 585240 **/
+
+  SimpleTest.waitForExplicitFinish();
+
+  window.onmessage = function(event) {
+    ok(true, "message event should fire!");
+    SimpleTest.finish();
+  }
+  window.postMessage("hello", "*");  
+
+</script>
+</pre>
+</body>
+</html>
