title: scroll div over another div
body: <p>I have two div with a height of 100%.
  And when you scroll, I want that the second div over the other scrolls, without scrolling the first up.</p>
  
  <p>Like on this site: <a href="http://www.endzeit-ausstellung.de/" rel="noreferrer">http://www.endzeit-ausstellung.de/</a></p>
  
  <p>I looked in Firebug, but I can't find the solution there, can anybody help me?</p>
  
  <p>Much thanks in advance!</p>