代码简介：
常用于后台的JS多级树形目录，代码虽然老，但很实用。
代码内容：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE>常用于后台的JS多级树形目录_网页代码站(www.webdm.cn)</TITLE>
<META http-equiv=Content-Type content="text/html; charset=gb2312">
<style>
td{text-align:left;font-size:9pt}
a{text-decoration:none}
</style>
</HEAD>
<SCRIPT LANGUAGE="JavaScript">
function ShowSub(theId)
{
theFo = eval("fold_" + theId);
if (theFo.style.display == "none")
{
theFo.style.display = "block";
}
else
{
theFo.style.display = "none";
}/*
for (i = 0; i < 7; i++)
{
if (i == theId)
continue;
theFo = eval("tr_" + i);
theFo.style.display = "none";
}*/
}
//-->
</SCRIPT>
<BODY>
<table>
<!--主目录1-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0')">软件下载</a></td>
</tr>
<!--主目录1下->1级子目录1-->
<tr id='fold_0' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
<table>
<!--2级子目录0_01-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_01')">常用工具</td>
</tr>
<tr id='fold_0_01' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
<table>
<!--3级子目录0_01_01-->
<tr>
<td colspan=2><img src="foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_01_01')">输入法</td>
</tr>
<tr id='fold_0_01_01' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
智能ABC<br>
万能五笔<br>
智能五笔<br>
</td>
</tr>
<!--3级子目录0_01_02-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_01_02')">杀毒软件</td>
</tr>
<tr id='fold_0_01_02' style="display:none">
<td width='13px' background='line1.gif'></td><!--缩进-->
<td>
软件补丁<br>
病毒库<br>
病毒信息<br>
</td>
</tr>
<!--3级子目录0_01_03-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_01_03')">压缩解压</td>
</tr>
<tr id='fold_0_01_03' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
winZip<br>
winRar<br>
</td>
</tr>
</table>
</td>
</tr>
<!--2级子目录0_02-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_02')">系统工具</td>
</tr>
<tr id='fold_0_02' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
<table>
<!--3级子目录0_02_01-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_02_01')">系统维护</td>
</tr>
<tr id='fold_0_02_01' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
磁盘修复<br>
磁盘清理<br>
系统修复<br>
</td>
</tr>
<!--3级子目录0_02_02-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_02_02')">系统测试</td>
</tr>
<tr id='fold_0_02_02' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
硬件检测<br>
性能测试<br>
</td>
</tr>
<!--3级子目录0_02_03-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('0_02_03')">系统补丁</td>
</tr>
<tr id='fold_0_02_03' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
windows2000补丁<br>
windows2003补丁<br>
windowsXp补丁
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
<!--主目录2-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('1')">硬件资讯</a></td>
</tr>
<!--主目录1下->1级子目录1-->
<tr id='fold_1' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
<table>
<!--2级子目录1_01-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('1_01')">产业资讯</td>
</tr>
<tr id='fold_1_01' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
国内业界<br>
国际业界<br>
热门专题<br>
</td>
</tr>
<!--2级子目录1_02-->
<tr>
<td colspan=2><img src="http://www.webdm.cn/images/20100106/foldericon.gif" WIDTH="16" HEIGHT="16">
<a href="javascript:ShowSub('1_02')">今日报价</td>
</tr>
<tr id='fold_1_02' style="display:none">
<td width='13px' background='http://www.webdm.cn/images/20100106/line1.gif'></td><!--缩进-->
<td>
笔记本<br>台式机<br>MP3
</td>
</tr>
</table>
</td>
</tr>
</table>
</BODY>
</HTML>
<br>
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代码来自：http://www.webdm.cn/webcode/efdf1130-9a15-4e2e-a898-577057f1f85a.html