CSS Tab切换效果

<style>
*{
padding:0;
margin:0;
font:normal normal 12px/1.5em "宋体";
}
#main{
margin:20px;
}
ul{
padding:0;
margin:0;
width:600px;
}
#tab li{
list-style:none;
float:left;
text-align:center;
padding:0;
}
#tab a{
display:block;
text-decoration:none;
width:94px;
line-height:24px;
}
#cont{
clear:both;
border:1px solid blue;
border-top:0;
width:562px!important;
width:564px;
height:190px;
overflow-y:hidden;
}
.common{
margin:5px;
}
.common li{
list-style:none;
padding-left:14px!important;
padding-left:0;
padding-top:4px;
}
.common li a{
text-decoration:none;
}
.common li a:hover{
color:red;
}
.on{
background:url(/tabmenu/hover_tab.gif) no-repeat left bottom;
}
.off{
background:url(/tabmenu/normal_tab.gif) no-repeat left bottom;
}
</style>
<script>
function $(ID){
return document.getElementById(ID)
}
function showTab(ID){
for(var i=1;i<7;i++){
if(ID==i){
$('tab'+i).blur();
$("tab"+i).className="on";
$("cont"+i).style.display="block";
}else{
$("tab"+i).className="off";
$("cont"+i).style.display="none";
}
}
return false;
}
</script>
<div id="main">
<div id="tab">
<ul>
<li><a href="javascript:void(0)" id="tab1" class="on" onclick="showTab('1')">流行音乐</a></li>
<li><a href="javascript:void(0)" id="tab2" class="off" onclick="showTab('2')">美女写真</a></li>
<li><a href="javascript:void(0)" id="tab3" class="off" onclick="showTab('3')">平面设计</a></li>
<li><a href="javascript:void(0)" id="tab4" class="off" onclick="showTab('4')">网络学堂</a></li>
<li><a href="javascript:void(0)" id="tab5" class="off" onclick="showTab('5')">恋爱宝典</a></li>
<li><a href="javascript:void(0)" id="tab6" class="off" onclick="showTab('6')">我的最爱</a></li>
</ul>
</div>
<div id="cont" >
<div id="cont1" class="common" style="display:block;">
<li><a href="javascript:void(0)">老婆最大</a></li>
<li><a href="javascript:void(0)">爱情买卖</a></li>
<li><a href="javascript:void(0)">爱情专属权</a></li>
<li><a href="javascript:void(0)">打劫爱情</a></li>
<li><a href="javascript:void(0)">求佛</a></li>
<li><a href="javascript:void(0)">香水有毒</a></li>
<li><a href="javascript:void(0)">生都要爱</a></li>
<li><a href="javascript:void(0)">秋天不回来</a></li>
</div>
<div style="display:none;" id="cont2" class="common">
<li><a href="javascript:void(0)">美女写真</a></li>
<li><a href="javascript:void(0)">美女写真</a></li>
<li><a href="javascript:void(0)">美女写真</a></li>
<li><a href="javascript:void(0)">美女写真</a></li>
<li><a href="javascript:void(0)">美女写真</a></li>
<li><a href="javascript:void(0)">美女写真</a></li>
<li><a href="javascript:void(0)">美女写真</a></li>
<li><a href="javascript:void(0)">美女写真</a></li>
</div>
<div style="display:none;" id="cont3" class="common">
<li><a href="javascript:void(0)">平面设计</a></li>
<li><a href="javascript:void(0)">平面设计</a></li>
<li><a href="javascript:void(0)">平面设计</a></li>
<li><a href="javascript:void(0)">平面设计</a></li>
<li><a href="javascript:void(0)">平面设计</a></li>
<li><a href="javascript:void(0)">平面设计</a></li>
<li><a href="javascript:void(0)">平面设计</a></li>
<li><a href="javascript:void(0)">平面设计</a></li>
</div>
<div style="display:none;" id="cont4" class="common">
<li><a href="javascript:void(0)">网络学堂</a></li>
<li><a href="javascript:void(0)">网络学堂</a></li>
<li><a href="javascript:void(0)">网络学堂</a></li>
<li><a href="javascript:void(0)">网络学堂</a></li>
<li><a href="javascript:void(0)">网络学堂</a></li>
<li><a href="javascript:void(0)">网络学堂</a></li>
<li><a href="javascript:void(0)">网络学堂</a></li>
<li><a href="javascript:void(0)">网络学堂</a></li>
</div>
<div style="display:none;" id="cont5" class="common">
<li><a href="javascript:void(0)">恋爱宝典</a></li>
<li><a href="javascript:void(0)">恋爱宝典</a></li>
<li><a href="javascript:void(0)">恋爱宝典</a></li>
<li><a href="javascript:void(0)">恋爱宝典</a></li>
<li><a href="javascript:void(0)">恋爱宝典</a></li>
<li><a href="javascript:void(0)">恋爱宝典</a></li>
<li><a href="javascript:void(0)">恋爱宝典</a></li>
<li><a href="javascript:void(0)">恋爱宝典</a></li>
</div>
<div style="display:none;" id="cont6" class="common">
<li><a href="javascript:void(0)">我的最爱</a></li>
<li><a href="javascript:void(0)">我的最爱</a></li>
<li><a href="javascript:void(0)">我的最爱</a></li>
<li><a href="javascript:void(0)">我的最爱</a></li>
<li><a href="javascript:void(0)">我的最爱</a></li>
<li><a href="javascript:void(0)">我的最爱</a></li>
<li><a href="javascript:void(0)">我的最爱</a></li>
<li><a href="javascript:void(0)">我的最爱</a></li></div>
</div>
</div>

 hover_tab.gif

normal_tab.gif