css:
复制代码 代码如下:
.main
{
height:360px;
width:290px;
border:1px solid #444444;
font-size:12px;
color:#444444;
margin:20px;
}
.main_top
{
height:30px;
width:290px;
line-height:30px;
text-align:left;
background-color:#999999;
border-bottom:1px solid #444444;
}
.main_top ul
{
padding:0px;
margin:0px;
list-style-type:none;
position:absolute;
}
.main_top ul li.h_qian
{
float:left;
width:80px;
text-align:center;
background-color:#999999;
height:30px;
}
.main_top ul li.h_hou
{
float:left;
width:80px;
text-align:center;
background-color:#ffffff;
cursor:pointer;
margin-top:1px;
height:30px;
font-weight:bold;
}
.main_content
{
margin:10px;
}

　js:
复制代码 代码如下:
function tabchange(obj,p,c,q,h) {
$(obj).parent().find("li").attr("class", ""+q+"");
$(obj).parents("."+p+"").find("."+c+"").hide();
$(obj).attr("class", ""+h+"");
var j = $(obj).index();
$(obj).parents("."+p+"").find("."+c+":eq(" + j + ")").show();
}

html:
复制代码 代码如下:
<div class="main">
<div class="main_top">
<ul>
<li class="h_hou" onmouseover="tabchange(this,'main','main_content','h_qian','h_hou')">第一模块</li>
<li class="h_qian" onmouseover="tabchange(this,'main','main_content','h_qian','h_hou')">第二模块</li>
<li class="h_qian" onmouseover="tabchange(this,'main','main_content','h_qian','h_hou')">第三模块</li>
</ul>
</div>
<div class="main_content">第1块
</div>
<div class="main_content" style="display:none;">第2块
</div>
<div class="main_content" style="display:none;">第3块
</div>
</div>

代码很简单，不多说了，详细使用方法请参照Demo中tangtab.js里的注释。

附：
在线演示：http://demo.jb51.net/js/2012/TabDemo/
打包下载：TabDemo_jb51.rar