title: How to get maximum document scrolltop value
body: <p>I am making some plugin and I need to get maximum <code>scrollTop</code> value of the document.
  Maximum <code>scrollTop</code> value is <code>2001</code> , but <code>$(document).height()</code> returns <code>2668</code> and <code>$('body')[0].scrollHeight</code> gives me <code>undefined</code>.</p>
  
  <p>How to get <code>2001</code> through javascript/jquery?!</p>