纯CSS二级菜单
<!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=gb2312" />
<title>无标题文档</title>
<style>
ul { margin:0; padding:0; list-style:none;}
.aa ul li { position:relative; display:inline; float:left;}
.aa ul li a { display:block; height:auto;}
.aa ul li ul { display:none;}
.aa ul li:hover ul { display:block; position:absolute; width:100%;}
.aa ul li:hover ul li a { height:auto; display:block; float:left;}
</style>
</head>
<body>
<divclass="aa">
<ul>
<li><a href="
http://www.lanrendy.com">aaaaaaa</a>
<ul>
<li><a href="
http://www.lanrendy.com">bbbbbb</a></li>
<li><a href="
http://www.lanrendy.com">cccccc</a></li>
</ul>
</li>
</ul>
</div>
</body>
</html>