title: Is cross-origin postMessage broken in IE10?
body: <p>I'm trying to make a trivial <code>postMessage</code> example work...</p>
  <ul>
  <li>in IE10</li>
  <li>between windows/tabs (vs. iframes)</li>
  <li>across origins</li>
  </ul>
  <p>Remove any one of these conditions, and things work fine :-)</p>
  <p>But as far as I can tell, between-window <code>postMessage</code> only appears to work in IE10 when both windows share an origin.  (Well, in fact -- and weirdly -- the behavior is slightly more permissive than that: two different origins that share a <em>host</em> seem to work, too).</p>
  <h1>Is this a documented bug? Any workarounds or other advice?</h1>
  <p>(Note: <a href="http://social.msdn.microsoft.com/Forums/en-US/iewebdevelopment/thread/a5b0acb7-0978-4677-98be-391144eb5601/" rel="noreferrer">This question</a> touches on the issues, but <a href="http://social.msdn.microsoft.com/Forums/en-US/iewebdevelopment/thread/a5b0acb7-0978-4677-98be-391144eb5601/" rel="noreferrer">its answer</a> is about IE8 and IE9 -- not 10)</p>
  <hr />
  <p>More details + example...</p>
  <h3>launcher page <a href="http://jsbin.com/ahuzir/1" rel="noreferrer">demo</a></h3>
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
    &lt;script&gt;
      window.addEventListener(&quot;message&quot;, function(e){
        console.log(&quot;Received message: &quot;, e);
      }, false);
    &lt;/script&gt;
    &lt;button onclick=&quot;window.open('http://jsbin.com/ameguj/1');&quot;&gt;
      Open new window
    &lt;/button&gt;
  &lt;/html&gt;
  </code></pre>
  <h3>launched page <a href="http://jsbin.com/ameguj/1" rel="noreferrer">demo</a></h3>
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
    &lt;script&gt;
      window.opener.postMessage(&quot;Ahoy!&quot;, &quot;*&quot;);
    &lt;/script&gt;
  &lt;/html&gt;
  </code></pre>
  <p>This works at: <a href="http://jsbin.com/ahuzir/1" rel="noreferrer">http://jsbin.com/ahuzir/1</a> -- because both pages are hosted at the same origin (jsbin.com).  But move the second page anywhere else, and it fails in IE10.</p>