自己动手、丰衣足食！<菜单导航栏------不简单>

<!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=utf-8" />
<title>无标题文档</title>
<style type="text/css">
.a1
{    width:100px;
    height:50px;
    top:200px;
    left:200px;
    background-color:#0F6;
    position:absolute;
    overflow:hidden;
}
.a11
{
    width:100px;
    height:50px;
    top:200px;
    left:200px;
    background-color:#0F6;
    position:absolute;
}
.b
{
    width:50px;
    height:150px;
    top:50px;
    left:0px;
    background-color:#FFF;
    position:absolute;
}
.a2
{
    width:100px;
    height:50px;
    top:0px;
    left:0px;
    background-color:#309;
    position:absolute;
    overflow:hidden    ;    
}
.a22
{
    width:100px;
    height:50px;
    top:0px;
    left:0px;
    background-color:#309;
    position:absolute;    
}
.a222
{
    width:100px;
    height:150px;
    top:0px;
    left:100px;
    background-color:#309;
    position:absolute;
}
.a3
{
    width:100px;
    height:50px;
    top:50px;
    left:0px;
    background-color:#F00;
    position:absolute;
    overflow:hidden;
}
.a33
{
    width:100px;
    height:50px;
    top:50px;
    left:0px;
    background-color:#F00;
    position:absolute;
}
.a333
{
    width:100px;
    height:150px;
    top:0px;
    left:100px;
    background-color:#F00;
    position:absolute;
}
.a4
{
    width:100px;
    height:50px;
    top:100px;
    left:0px;
    background-color:#FF0;
    position:absolute;
    overflow:hidden;
}
.a44
{
    width:100px;
    height:50px;
    top:100px;
    left:0px;
    background-color:#FF0;
    position:absolute;
}
.a444
{
    width:100px;
    height:150px;
    top:0px;
    left:100px;
    background-color:#FF0;
    position:absolute;
}
</style>
</head>

<body>
<div class="a1" onmouseover="className='a11'" onmouseout="className='a1'">
<div class="b">
   <div class="a2" onmouseover="className='a22'" onmouseout="className='a2'">
   <div class="a222"></div>
   </div>
      <div class="a3" onmouseover="className='a33'" onmouseout="className='a3'">
      <div class="a333"></div>
      </div>
         <div class="a4" onmouseover="className='a44'" onmouseout="className='a4'">
         <div class="a444"></div>
         </div>  
</div>
</div>
</body>
</html>
运行效果