title: detect distance scrolled from top jquery
body: <p>How can I detect the number of pixels scrolled in a browser window? 
  I need this to dynamically adjust the height of a 100% height div... </p>
  
  <p>I'm using jQuery.</p>
  
  <p>EDIT: I cannot just use scrollTop() because I'm working with a 100% height div with overflow set to auto. Firefox does not detect browser scrolling due to this, the only thing scrolling is a 100%x100% div...</p>