title: IE8/9 window.postMessage not working, but why?
body: <p>The "postMessage" is an HTML5 API, it is available in all major browsers including IE8/9. What I am trying to do is to create a popup window from a page, and be able to talk to the popup window using "postMessage". This works in every browser except IE8/9. Disappointed!</p>
  
  <p>It looks like IE8/9 only allows the communication between iframes, but not between two windows, even the windows are within the same hierarchy.</p>