title: viewport of browser from cross-site iframe
body: <p>I need to find out the browser viewport size from within a cross-domain iframe. The <a href="https://stackoverflow.com/questions/1860524/javascript-how-to-find-out-width-and-height-of-viewpoint-in-browser-window/1860596#1860596">normal method</a> doesn't work because it only gets the viewport of the iframe. If I use <code>top.innerHeight</code>, etc. in a cross-domain situation, I run into security issues. Is there a different property/method I can use? Cross-browser would be ideal, but even getting this on a single browser would be helpful.</p>
  
  <p>(I'm trying to find out if my iframe is in view or not.)</p>