title: Skrollr: how to start animation only once a certain point is reached?
body: <p>I'm playing with <a href="http://prinzhorn.github.io/skrollr/" rel="nofollow">skrollr plugin</a> but can't achieve what I want so looking for assistance.
  I've been able to implement easy effects such as <code>&lt;div id="intro-left" data-0="opacity: 0" data-180="opacity: 1"&gt;</code> (means that my DIV called intro-left becomes visible once user scrolls down by 180)</p>
  
  <p>The issue is that I don't like to use the scrolling distance since this would only makes sense  if everone had the same screen resolution right?</p>
  
  <p>What I'd like to do is to tell skrollr: "Change DIV from opacity 0 to opacity 1 once the DIV position becomes visible on the screen" (in other words "Change DIV from opacity 0 to opacity 1 once user reaches a certain point on the page by scrolling down)</p>
  
  <p>Is this achievable with skrollr, and how?</p>
  
  <p>Many thanks</p>