title: Detect Document Height Change
body: <p>I'm trying to detect when my <code>document</code> height changes.  Once it does, I need to run a few functions to help organize my page layout.</p>
  
  <p>I'm not looking for <code>window.onresize</code>.  I need the entire document, which is larger than the window.</p>
  
  <p>How do I observe this change?</p>