<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
.one li {
100px;
height: 30px;
line-height: 30px;
background: url(nav/libg.jpg) no-repeat;
//float: left;
text-align: center;
margin-left: 10px;
cursor: pointer;
_display: inline;
position: relative;
}
li ul {
position: absolute;
left: 0;
top: 30px;
display: none;
}
.cd{
margin-top: -30px;
margin-left: 65px;
}
li{
list-style: none;
}
</style>
</head>
<body>
<ul class="one">
<li id="li01">
<span>一级菜单</span>
<ul id="ul01"class="cd" >
<li>二级菜单</li>
<li>二级菜单</li>
<li>二级菜单</li>
</ul>
</li>
<li id="li02">
<span>一级菜单</span>
<ul id="ul02" class="cd" >
<li>二级菜单</li>
<li>二级菜单</li>
<li>二级菜单</li>
</ul>
</li>
<li id="li03">
<span >一级菜单</span>
<ul id="ul03"class="cd" >
<li>二级菜单</li>
<li>二级菜单</li>
<li>二级菜单</li>
</ul>
</li>
</ul>
<script>
function fn(canshu1,canshu2){
var li01 = document.getElementById(canshu1);
var ul01 = document.getElementById(canshu2);
li01.onmouseover = function(){
ul01.style.display = "block"
}
li01.onmouseout = function(){
ul01.style.display = "none"
}
}
fn("li01","ul01")
fn("li02","ul02")
fn("li03","ul03")
</script>
</body>
</html>