原文地址：http://www.cnblogs.com/yes123/p/3944046.html
JavaScript下拉菜單的例子分享
css+js下拉菜單
完整代碼：
<!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 runat="server">
<title>JavaScript下拉菜單-www.yuju100.com-語句百分網</title>
<style type="text/css">
* {
padding:0;
margin:0;
}
body {
font-family:verdana, sans-serif;
font-size:small;
}
#navigation, #navigation li ul {
list-style-type:none;
}
#navigation {
margin:20px;
}
#navigation li {
float:left;
text-align:center;
position:relative;
}
#navigation li a:link, #navigation li a:visited {
display:block;
text-decoration:none;
color:#000;
width:120px;
height:40px;
line-height:40px;
border:1px solid #fff;
border-width:1px 1px 0 0;
background:#c5dbf2;
padding-left:10px;
}
#navigation li a:hover {
color:#fff;
background:#2687eb;
}
#navigation li ul li a:hover {
color:#fff;
background:#6b839c;
}
#navigation li ul {
display:none;
position:absolute;
top:40px;
left:0;
margin-top:1px;
width:120px;
}
#navigation li ul li ul {
display:none;
position:absolute;
top:0px;
left:130px;
margin-top:0;
margin-left:1px;
width:120px;
}
</style>
<script type="text/javascript">
function displaySubMenu(li) {
var subMenu = li.getElementsByTagName("ul")[0];
subMenu.style.display = "block";
}
function hideSubMenu(li) {
var subMenu = li.getElementsByTagName("ul")[0];
subMenu.style.display = "none";
}
</script>
</head>
<body>
<ul id="navigation">
<li onmouseout="hideSubMenu(this)">
<a href="#">欄目1</a>
<ul>
<li><a href="#">欄目1->菜單1</a></li>
<li><a href="#">欄目1->菜單2</a></li>
<li><a href="#">欄目1->菜單3</a></li>
<li><a href="#">欄目1->菜單4</a></li>
</ul>
</li>
<li onmouseout="hideSubMenu(this)">
<a href="#">欄目2</a>
<ul>
<li><a href="#">欄目2->菜單1</a></li>
<li><a href="#">欄目2->菜單2</a></li>
<li><a href="#">欄目2->菜單3</a></li>
<li><a href="#">欄目2->菜單4</a></li>
<li><a href="#">欄目2->菜單5</a></li>
</ul>
</li>
<li onmouseout="hideSubMenu(this)">
<a href="#">欄目3</a>
<ul>
<li onmouseout="hideSubMenu(this)">
<a href="#">欄目3->菜單1</a>
<ul>
<li><a href="#">菜單1->子菜單1</a></li>
<li><a href="#">菜單1->子菜單2</a></li>
<li><a href="#">菜單1->子菜單3</a></li>
<li><a href="#">菜單1->子菜單4</a></li>
</ul>
</li>
<li><a href="#">欄目3->菜單2</a></li>
<li onmouseout="hideSubMenu(this)">
<a href="#">欄目3->菜單3</a>
<ul>
<li><a href="#">菜單3->子菜單1</a></li>
<li><a href="#">菜單3->子菜單2</a></li>
<li><a href="#">菜單3->子菜單3</a></li>
</ul>
</li>
</ul>
</li>
</ul>
</body>
</html>
個人感覺這個js菜單還不錯，小巧精練，很實用。