title: jquery ul li first-child change color
body: <p>I am working for a simple menu, click each top menu, open sub menu, and set the first-child different background-color.</p>
  
  <p>Code in here: <a href="http://jsfiddle.net/X3Dey/" rel="nofollow">http://jsfiddle.net/X3Dey/</a></p>
  
  <p>Thanks.</p>
  
  <p>​</p>