title: postMessage not being received from iframe
body: <p>Here is the code in the iframe with <code>src="example.com"</code></p>
  
  <pre><code>&lt;script&gt;
  
      var domain = "http://example2.com";
  
      function redirectRequest(){
  
          console.log("window.opener",window.opener); // NULL
          console.log("window.top",window.top); // script_name
          console.log("window.parent",window.parent); // script_name
  
          opener.postMessage("redirect", domain); //fails because null
         //top and parent also do not work BUT do not display errors
      }
  
  &lt;/script&gt;
  </code></pre>
  
  <p>and here is the code running in <code>example2.com</code> which contains the postMessage receiver (and also contains the iframe):</p>
  
  <pre><code>function message_listener(event) { //nothing is ever received...
  
     console.log("event received",event); 
  
     var data = event.data;
  
     console.log("data received",data);
  
  }
  
  
  if (window.addEventListener) {
     window.addEventListener("message", message_listener);
  } else {
     // IE8
     window.attachEvent("onmessage", message_listener);
  }
  </code></pre>
  
  <p>Any idea what might be off? Thank you very much...</p>