title: Change navigation active class on window scroll
body: <p>i want to create a scroll effect like here  <a href="http://www.strikingly.com/s/pages/default-ion?demo=ion#1" rel="noreferrer">http://www.strikingly.com/s/pages/default-ion?demo=ion#1</a>
  All i need for this moment is to change navigation li class active when the window is scrolling , just change the it using <code>&lt;a href='#about'&gt;</code> hash target</p>
  
  <p><a href="http://jsfiddle.net/Dxtyu/131/" rel="noreferrer">http://jsfiddle.net/Dxtyu/131/</a>  </p>