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<meta charset="utf-8">
<title>js版本下拉菜单</title>
<style>
*{ margin:0; padding:0; list-style:none;}
a{ text-decoration:none; color:#000;}
#top{ margin:0 auto; 980px;}
.top-nav{ height:40px;}
.top-nav li{ float:left;200px; line-height:40px; background:#E5383B;}
.top-nav li a{ display:block; text-align:center; color:#fff;}
.top-nav li a:hover{ background:#FC6D70; color:#F0F0F0;}
.top-nav li .se-nav{ display:none;}
.top-nav li .se-nav li{ height:45px; line-height:45px;}
</style>
<script type="text/javascript">
window.onload=function(){
var oTop=document.getElementById('top');
var oTopNav=document.getElementById('topNav');
var aLi=document.getElementsByTagName('li');
for(var i=0;i<aLi.length;i++){
aLi[i].onmouseover=function(){
var seNav=this.getElementsByTagName('ul')[0]
if(seNav!=undefined){
seNav.style.display='block';
}
}
aLi[i].onmouseout=function(){
var seNav=this.getElementsByTagName('ul')[0]
if(seNav!=undefined){
seNav.style.display='none';
}
}
}
}
</script>
</head>
<body>
<div id="top">
<ul class="top-nav" id="topNav">
<li><a href="#">首页</a></li>
<li>
<a href="#">课程大厅</a>
<ul class="se-nav">
<li><a href="#">javascript</a></li>
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<li><a href="#">jquery</a></li>
</ul>
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<li><a href="#">javascript</a></li>
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