<!doctype html>
<html lang="zh-cn">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
body,ul,li{margin:0; padding:0; list-style:none}
ul li{width:100px; height:100px; border:1px solid #f00; float:left; margin:50px 10px; background-color:#ffffff;}
ul li.current{border:1px solid #dfdfdf; background-color:#ff0000;}
</style>
<script type="text/javascript" src="
http://ajax.googleapis.com/ajax/libs/jquery/1.4.0/jquery.min.js"></script>
</head>
<body>
<h1>鼠标经过下面的块</h1>
<ul>
<li></li>
<li></li>
<li></li>
<li></li>
</ul>
</body>
</html>
<script type="text/javascript">
$("ul li").mouseover(function()
{
$(this).addClass("current");
}).mouseout(function()
{
$(this).removeClass("current");
});
</script>