仿QQ面板风格的多级折叠、展开菜单，三级下拉导航，JavaScript+CSS共同结晶的结果，推荐给大家，点击“运行”可查看效果。
http://www.ij2ee.com/ http://www.gbsou.com/
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>下拉菜单</title>
<style type="text/css">
*{ margin:0px; padding:0px; border:0px; }
body{ font-size:12px; color:#333;text-align:center;}
.mbox{background:#73C2FF; width:184px; height:auto;}
.mbox .m1{background:url(http://www.codefans.net/jscss/demoimg/201104/m1.gif) no-repeat left; width:182px; height:25px; line-height:25px; color:#4B6486; font-size:14px; font-weight:700;text-align:left; text-indent:19px;}
.mbox .m2{background:url(http://www.codefans.net/jscss/demoimg/201104/m2.gif) no-repeat left; width:182px; height:25px; line-height:25px; color:#4B6486; font-size:14px; font-weight:700; text-align:left;text-indent:19px;}
.mbox .Test5study{ background:#fff;}
.mbox .Test5study{text-align:left;width:182px;height:auto;overflow: hidden;}
.mbox .Test5study h2{font-size:14px;height:22px;line-height:22px;background:#E5F5FF;text-indent:10px;position:relative;border-top: 1px solid #fff;border-bottom: 1px solid #A9DAFF; font-weight:normal;cursor:pointer;}
.mbox .Test5study h2 span{font-weight: normal;position:absolute;top:0;right:6px;}
.mbox .Test5study li{border-bottom:dashed 1px #eee; line-height:22px;}
.mbox .Test5study {border-bottom:solid 1px #A9DAFF;}
.mbox .TxtList{ list-style:disc url(); padding:10px 0 10px 10px; height:200px; overflow-y:scroll;}
</style>
<script language="javascript" id="clientEventHandlersJS">
<!--
var number=2;
function LMYC() {
var lbmc;
//var treePic;
for (i=1;i<=number;i++) {
lbmc = eval('LM' + i);
//treePic = eval('treePic'+i);
//treePic.src = 'images/file.gif';
lbmc.style.display = 'none';
}
}
function ShowFLT(i) {
lbmc = eval('LM' + i);
//treePic = eval('treePic' + i)
if (lbmc.style.display == 'none') {
LMYC();
//treePic.src = 'images/nofile.gif';
lbmc.style.display = '';
}
else {
//treePic.src = 'images/file.gif';
lbmc.style.display = 'none';
}
}
//-->
</script>
</head>
<body>
<div class="mbox">
<div class="m1" ><a onClick="javascript:ShowFLT(1)" href="javascript:void(null)" style="text-decoration:none; color:#4B6486">标题1</a></div>
<div id="LM1" style="DISPLAY: none">
<div id="Test5study" class="Test5study">
<h2 id="t1" onClick="ShHi('t1','h1');">传说中的标题</h2>
<ul class="TxtList" id="h1" >
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
<h2 id="t2" onClick="ShHi('t2','h2');">传说中的标题</h2>
<ul class="TxtList" id="h2" style="display:none;">
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
<h2 id="t3" onClick="ShHi('t3','h3');">传说中的标题</h2>
<ul class="TxtList" id="h3" style="display:none;">
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
<h2 id="t4" onClick="ShHi('t4','h4');">传说中的标题</h2>
<ul class="TxtList" id="h4" style="display:none;">
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
</div>
</div>
</div>
<div class="mbox">
<div class="m1" ><a onClick="javascript:ShowFLT(2)" href="javascript:void(null)" style="text-decoration:none; color:#4B6486">标题2</a></div>
<div id="LM2" style="DISPLAY: none">
<div id="Test5study" class="Test5study">
<h2 id="t5" onClick="ShHi('t5','h5');">传说中的标题2</h2>
<ul class="TxtList" id="h5" >
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
<h2 id="t6" onClick="ShHi('t6','h6');">传说中的标题2</h2>
<ul class="TxtList" id="h6" style="display:none;">
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
<h2 id="t7" onClick="ShHi('t7','h7');">传说中的标题2</h2>
<ul class="TxtList" id="h7" style="display:none;">
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
<h2 id="t8" onClick="ShHi('t8','h8');">传说中的标题2</h2>
<ul class="TxtList" id="h8" style="display:none;">
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
<li>春天的脚步越来越近了</li>
</ul>
</div>
</div>
</div>
<script type="text/javascript">
function $(d){return document.getElementById(d);}
function f(d){var t=$(d);if (t){return t.style;}else{return null;}}
function Hi(){var items = document.getElementsByTagName("ul");for (var i=0;i<items.length;i++){items[i].style.display='none';}}
function Hl(){var iteml = document.getElementsByTagName("h2");for (var j=0;j<iteml.length;j++){iteml[j].style.fontWeight='normal';}}
function h(d){var s=f(d);var b=s.display;if (b=='none'){return true;}else{return false;}}
function ShHi(ii,jj){if(h(jj)){Hl();Hi();f(jj).display='block';f(ii).fontWeight='bold';}else{Hl();Hi();f(jj).display='none';f(ii).fontWeight='normal';}}
</script>
</body>
</html>
