title: HTML menu active section illumination
body: <p>How do I make the color of a section change in a HTML menu made of DIVs when that section is selected?</p>
  
  <p>Basically, I am creating a menu such as the one on the left of this image:
  <a href="http://docs.shopify.com/assets/images/manual/orders/orders.jpg?1386029140" rel="nofollow">http://docs.shopify.com/assets/images/manual/orders/orders.jpg?1386029140</a></p>
  
  <p>How do I make the corresponding section we are on to be "illuminated"?</p>
  
  <p>Do I do it with PHP and having a variable for each div's class?</p>