代码简介：
二级树形菜单示例：CSS TreeMenu ，非常漂亮的树形菜单，用在网站右侧比较合适。
代码内容：
<!doctype html public "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<head>
<title>适合放在网站右侧的CSS二级树形菜单_网页代码站(www.webdm.cn)</title>
<style type="text/css" media="all">
a,a:visited {color:#333;text-decoration:none;}
a:hover {color:#f60;}
body,td {font:13px "Geneva","宋体", "Arial", "Helvetica",sans-serif;}
ul,li {margin:0;padding:0;list-style:none;}
h1,h2,h3,h4,h5,h6 {margin:0;padding:0;}
h1 {padding:5px;color:#900;font:16px bold "Geneva","宋体", "Arial", "Helvetica",sans-serif;}
h1 small {font-size:11px;font-weight:normal;color:#660;}
.TreeWrap {200px;}
.MenuBox .titBox a,
.MenuBox .titBox a:visited,
.MenuBox2 .titBox a,
.MenuBox2 .titBox a:visited {margin-left:10px;padding-left:40px;color:#003;font-size:12px;display:block;}
.MenuBox .titBox h3 a {background:url(http://www.webdm.cn/images/20101124/1/ico_folder_open.gif) no-repeat 0 40%;}
.MenuBox .titBox h3.Fst a {background:url(http://www.webdm.cn/images/20101124/1/ico_folder_open_fst.gif) no-repeat 0 40%;}
.MenuBox .titBox h3.Lst a {background:url(http://www.webdm.cn/images/20101124/1/ico_folder_open_lst.gif) no-repeat 0 40%;}
.MenuBox2 .titBox h3 a {background:url(http://www.webdm.cn/images/20101124/1/ico_folder.gif) no-repeat 0 40%;}
.MenuBox2 .titBox h3.Fst a {background:url(http://www.codefans.net/jscss/demoimg/201010/ico_folder_fst.gif) no-repeat 0 40%;}
.MenuBox2 .titBox h3.Lst a {line-height:250%;background:url(http://www.webdm.cn/images/20101124/1/con_exit.gif) no-repeat 0 0;}
.MenuBox2 .txtBox {display:none;}
.MenuBox .txtBox ul li {padding-left:65px;line-height:150%;}
.MenuBox .txtBox .num {color:#e00;}
.MenuBox .txtBox ul {background:url(http://www.webdm.cn/images/20101124/1/line_y.gif) repeat-y 16px 0;}
.MenuBox .txtBox ul li {background:url(http://www.webdm.cn/images/20101124/1/t.gif) no-repeat 28px 50%;}
.MenuBox .txtBox ul li.Lst {background:url(http://www.webdm.cn/images/20101124/1/t_lst.gif) no-repeat 28px 50%;}
</style>
<script type="text/javascript">
<!--
function ExChgClsName(Obj,NameA,NameB){
var Obj=document.getElementById(Obj)?document.getElementById(Obj):Obj;
Obj.className=Obj.className==NameA?NameB:NameA;
}
function showMenu(iNo){
ExChgClsName("Menu_"+iNo,"MenuBox","MenuBox2");
}
-->
</script>
</head>
<body>
<h1>CSS TreeMenu <small>By 枫岩@IECN.Net</small></h1>
<div class="TreeWrap">
<div class="MenuBox" id="Menu_0">
<div class="titBox"><h3 class="Fst"><a href="javascript:showMenu(0);">同事</a></h3></div>
<div class="txtBox">
<ul>
<li><a href="#">Dodo</a></li>
<li><a href="#">小春</a></li>
<li><a href="#">小林</a></li>
<li><a href="#">小龙</a></li>
<li class="Lst"><a href="#">枫岩</a></li>
</ul>
</div>
</div><!--MenuBox-->
<div class="MenuBox2" id="Menu_1">
<div class="titBox"><h3><a href="javascript:showMenu(1);">客户</a></h3></div>
<div class="txtBox">
<ul>
<li><a href="#">Dodo</a></li>
<li><a href="#">小春</a></li>
<li><a href="#">小林</a></li>
<li><a href="#">小龙</a></li>
<li class="Lst"><a href="#">枫岩</a></li>
</ul>
</div>
</div><!--MenuBox-->
<div class="MenuBox2" id="Menu_2">
<div class="titBox"><h3><a href="javascript:showMenu(2);">朋友</a></h3></div>
<div class="txtBox">
<ul>
<li><a href="#">Dodo</a></li>
<li><a href="#">小春</a></li>
<li><a href="#">小林</a></li>
<li><a href="#">小龙</a></li>
<li class="Lst"><a href="#">枫岩</a></li>
</ul>
</div>
</div><!--MenuBox-->
<div class="MenuBox2" id="Menu_3">
<div class="titBox"><h3><a href="javascript:showMenu(3);">家人</a></h3></div>
<div class="txtBox">
<ul>
<li><a href="#">Dodo</a></li>
<li><a href="#">小春</a></li>
<li><a href="#">小林</a></li>
<li><a href="#">小龙</a></li>
<li class="Lst"><a href="#">枫岩</a></li>
</ul>
</div>
</div><!--MenuBox-->
<div class="MenuBox2">
<div class="titBox"><h3 class="Lst"><a href="#">退出系统</a></h3></div>
</div><!--MenuBox-->
</div>
<br />
<p><a href="http://www.webdm.cn">网页代码站</a> - 最专业的网页代码下载网站 - 致力为中国站长提供有质量的网页代码！</p>
</body>
</html>
代码来自：http://www.webdm.cn/webcode/d221396c-48bc-42e5-a842-659f4f62ee4b.html