title: jQuery Show/Hide Div when Section is in Viewport
body: <p>My code at the moment is here: <a href="http://www.jaygeorge.co.uk/gwennan-sage" rel="nofollow">http://www.jaygeorge.co.uk/gwennan-sage</a></p>
  
  <p>You'll see two green arrows that are in a fixed position at the bottom of the page.
  I'm having trouble getting jQuery to hide these divs (#timeline-buttons) when the Timeline section is NOT in view, preferably using the fade() technique.</p>
  
  <p>I've tried a Viewport plugin but can't get it to work properly with if statements, I'm sure it can be done with normal jQuery by measuring div heights somehow.</p>
  
  <p>Any advice appreciated, thanks in advance.</p>