title: How to get the position of an iframe relative to the top window's viewport?
body: <p>I've got html like so:</p>
  
  <pre><code>&lt;body&gt;
      [some stuff]
      &lt;iframe src="pageWithMyScript.html"&gt;&lt;/iframe&gt;
      [more stuff]
  &lt;/body&gt;
  </code></pre>
  
  <p>I want to find the location of the iframe relative to window.top (and/or the top.document) from a script running inside the iframe. (Ideally this would be without any frameworks, though I can always deconstruct how they do it, I suppose.)</p>