title: Threading for iframe elements in IE
body: <p>Of the following, which are not run in the same thread as the current page in <strong>IE8</strong>?</p>
  
  <ul>
  <li>An iframe with the same domain as the current page.</li>
  <li>An iframe with a sub-domain of the current page's domain.</li>
  <li>An iframe with a super-domain of the current page's domain.</li>
  <li>An iframe with a completely different domain from the current page.</li>
  </ul>
  
  <p>I want to know this for implementing <a href="http://www.whatwg.org/specs/web-workers/current-work/" rel="nofollow noreferrer">Web Workers</a> in IE that are in separate threads.</p>
  
  <p><strong>Edit</strong>: Is there <em>any</em> way to have a <code>window</code> in another thread in IE to <code>postMessage</code> to?</p>