Button rollover with CSS

Posted by: Ping
There are a couple of ways for button rollover:
A. Button rollover with Javascript (treat the buttons as image links)
B. Button rollover with CSS

Download the reference file from here
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>DWWK</title>
<link href="dwwk.css" rel="stylesheet" type="text/css" />
</head>

<body>
<div id="container">
 <div id="header"></div>
 <div id="nav">
  <ul>
   <li id="nav_home"><a href="home.html">Home</a></li>
   <li id="nav_nav"><a href="nav.html">Navigation</a></li>
   <li id="nav_layout"><a href="layout.html">Layout</a></li>
   <li id="nav_type"><a href="type.html">Type</a></li>
   <li id="nav_img"><a href="img.html">Image</a></li>
   <li id="nav_map"><a href="map.html">Sitemap</a></li>
  </ul>
 </div>

</div>
</body>
</html>