三级折叠菜单和二级折叠菜单....无限级树形菜单

#menu { width:200px; margin:auto;}
 #menu h1 { font-size:12px; border:#C60 1px solid; margin-top:1px;  background-color:#F93;}
 #menu h2 { font-size:12px; border:#E7E7E7 1px solid; border-top-color:#FFF; background-color:#F4F4F4;}
 #menu ul { padding-left:15px; height:100px;border:#E7E7E7 1px solid; border-top:none;overflow:auto;}
 #menu a { display:block; padding:5px 0 3px 10px; text-decoration:none; overflow:hidden;}
 #menu a:hover{ color:#6F0; background:#000;}
 #menu .no {display:none;}
 #menu .h1 a{color:#6F0;}
 #menu .h2 a{color:#06F;}
 #menu  h1 a{color:#FFF;}

function ShowMenu(obj, n) {
    var Nav = obj.parentNode;
    if (!Nav.id) {
        var BName = Nav.getElementsByTagName("ul");
        var HName = Nav.getElementsByTagName("h2");
        var t = 2;
    } else {
        var BName = document.getElementById(Nav.id).getElementsByTagName("span");
        var HName = document.getElementById(Nav.id).getElementsByTagName("h1");
        var t = 1;
    }
    for (var i = 0; i < HName.length; i++) {
        HName[i].innerHTML = HName[i].innerHTML.replace("-", "+");
        HName[i].className = "";
    }
    obj.className = "h" + t;
    for (var i = 0; i < BName.length; i++) { if (i != n) { BName[i].className = "no"; } }
    if (BName[n].className == "no") {
        BName[n].className = "";
        obj.innerHTML = obj.innerHTML.replace("+", "-");
    } else {
        BName[n].className = "no";
        obj.className = "";
        obj.innerHTML = obj.innerHTML.replace("-", "+");
    }
}

<div id="menu">
 <h1 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 一级菜单A</a></a></h1>
 <span class="no">
  <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 一级菜单A_1</a></a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 一级菜单A_2</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,2)"><a href="javascript:void(0)">+ 一级菜单A_3</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,3)"><a href="javascript:void(0)">+ 一级菜单A_4</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,4)"><a href="javascript:void(0)">+ 一级菜单A_5</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,5)"><a href="javascript:void(0)">+ 一级菜单A_6</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,6)"><a href="javascript:void(0)">+ 一级菜单A_7</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,7)"><a href="javascript:void(0)">+ 一级菜单A_8</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,8)"><a href="javascript:void(0)">+ 一级菜单A_9</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,9)"><a href="javascript:void(0)">+ 一级菜单A_10</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,10)"><a href="javascript:void(0)">+ 一级菜单A_11</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,11)"><a href="javascript:void(0)">+ 一级菜单A_12</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">一级菜单A_0</a>
   <a href="javascript:void(0)">一级菜单A_1</a>
   <a href="javascript:void(0)">一级菜单A_2</a>
   <a href="javascript:void(0)">一级菜单A_3</a>
   <a href="javascript:void(0)">一级菜单A_4</a>
   <a href="javascript:void(0)">一级菜单A_5</a>
   <a href="javascript:void(0)">一级菜单A_6</a>
   <a href="javascript:void(0)">一级菜单A_7</a>
   <a href="javascript:void(0)">一级菜单A_8</a>
   <a href="javascript:void(0)">一级菜单A_9</a>
  </ul>
 </span>
        
 <h1 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 二级菜单B</a></h1>
 <span class="no">
  <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 二级菜单B_1</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">二级菜单B_0</a>
   <a href="javascript:void(0)">二级菜单B_1</a>
   <a href="javascript:void(0)">二级菜单B_2</a>
   <a href="javascript:void(0)">二级菜单B_3</a>
   <a href="javascript:void(0)">二级菜单B_4</a>
   <a href="javascript:void(0)">二级菜单B_5</a>
   <a href="javascript:void(0)">二级菜单B_6</a>
   <a href="javascript:void(0)">二级菜单B_7</a>
   <a href="javascript:void(0)">二级菜单B_8</a>
   <a href="javascript:void(0)">二级菜单B_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 二级菜单B_2</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">二级菜单B_0</a>
   <a href="javascript:void(0)">二级菜单B_1</a>
   <a href="javascript:void(0)">二级菜单B_2</a>
   <a href="javascript:void(0)">二级菜单B_3</a>
   <a href="javascript:void(0)">二级菜单B_4</a>
   <a href="javascript:void(0)">二级菜单B_5</a>
   <a href="javascript:void(0)">二级菜单B_6</a>
   <a href="javascript:void(0)">二级菜单B_7</a>
   <a href="javascript:void(0)">二级菜单B_8</a>
   <a href="javascript:void(0)">二级菜单B_9</a>
  </ul>
 </span>
    
 <h1 onClick="javascript:ShowMenu(this,2)"><a href="javascript:void(0)">+ 三级菜单C</a></h1>
 <span class="no">
  <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 三级菜单C_1</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">三级菜单C_0</a>
   <a href="javascript:void(0)">三级菜单C_1</a>
   <a href="javascript:void(0)">三级菜单C_2</a>
   <a href="javascript:void(0)">三级菜单C_3</a>
   <a href="javascript:void(0)">三级菜单C_4</a>
   <a href="javascript:void(0)">三级菜单C_5</a>
   <a href="javascript:void(0)">三级菜单C_6</a>
   <a href="javascript:void(0)">三级菜单C_7</a>
   <a href="javascript:void(0)">三级菜单C_8</a>
   <a href="javascript:void(0)">三级菜单C_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 三级菜单C_2</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">三级菜单C_0</a>
   <a href="javascript:void(0)">三级菜单C_1</a>
   <a href="javascript:void(0)">三级菜单C_2</a>
   <a href="javascript:void(0)">三级菜单C_3</a>
   <a href="javascript:void(0)">三级菜单C_4</a>
   <a href="javascript:void(0)">三级菜单C_5</a>
   <a href="javascript:void(0)">三级菜单C_6</a>
   <a href="javascript:void(0)">三级菜单C_7</a>
   <a href="javascript:void(0)">三级菜单C_8</a>
   <a href="javascript:void(0)">三级菜单C_9</a>
  </ul>
 </span>
    
 <h1 onClick="javascript:ShowMenu(this,3)"><a href="javascript:void(0)">+ 四级菜单D</a></h1>
 <span class="no">
  <h2 onClick="javascript:ShowMenu(this,0)"><a href="javascript:void(0)">+ 四级菜单D_1</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">四级菜单D_0</a>
   <a href="javascript:void(0)">四级菜单D_1</a>
   <a href="javascript:void(0)">四级菜单D_2</a>
   <a href="javascript:void(0)">四级菜单D_3</a>
   <a href="javascript:void(0)">四级菜单D_4</a>
   <a href="javascript:void(0)">四级菜单D_5</a>
   <a href="javascript:void(0)">四级菜单D_6</a>
   <a href="javascript:void(0)">四级菜单D_7</a>
   <a href="javascript:void(0)">四级菜单D_8</a>
   <a href="javascript:void(0)">四级菜单D_9</a>
  </ul>
  <h2 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">+ 四级菜单D_2</a></h2>
  <ul class="no">
   <a href="javascript:void(0)">四级菜单D_0</a>
   <a href="javascript:void(0)">四级菜单D_1</a>
   <a href="javascript:void(0)">四级菜单D_2</a>
   <a href="javascript:void(0)">四级菜单D_3</a>
   <a href="javascript:void(0)">四级菜单D_4</a>
   <a href="javascript:void(0)">四级菜单D_5</a>
   <a href="javascript:void(0)">四级菜单D_6</a>
   <a href="javascript:void(0)">四级菜单D_7</a>
   <a href="javascript:void(0)">四级菜单D_8</a>
   <a href="javascript:void(0)">四级菜单D_9</a>
  </ul>
 </span>
</div>

 -------------------------------------------------------------------------------

下面为二级折叠菜单

function ShowMenu(obj, n) {
    var Nav = obj.parentNode;
    if (!Nav.id) {
        var BName = Nav.getElementsByTagName("ul");
        var HName = Nav.getElementsByTagName("h2");
        var t = 2;
    } else {
        var BName = document.getElementById(Nav.id).getElementsByTagName("span");
        var HName = document.getElementById(Nav.id).getElementsByTagName("h1");
        var t = 1;
    }
    for (var i = 0; i < HName.length; i++) {

        //HName[i].innerHTML = HName[i].innerHTML.replace("-", "+");//点击另一个菜单时，本菜单样式更换
        HName[i].className = "";
    }
    obj.className = "h" + t;
    for (var i = 0; i < BName.length; i++) { if (i != n) { BName[i].className = "no"; } }
    if (BName[n].className == "no") {//一级菜单展开时
        BName[n].className = "";
        $(obj).addClass("Navleft1");
        //obj.innerHTML = obj.innerHTML.replace("+", "-");
    } else {
        BName[n].className = "no";
        obj.className = "";
        //obj.innerHTML = obj.innerHTML.replace("-", "+"); //一级菜单折叠时
    }
}

#Nav_left { width:100%; margin:auto;padding-bottom:10px; background:#f5f5f5;}
 #Nav_left h1 { border-bottom:#e3e3e3 1px solid; margin-top:1px; }
 #Nav_left h1 a { background:url(../images/jia.png) no-repeat   30px center;font-size:16px; display:inline-block; padding:0px 0 0px 50px;height:40px;line-height:40px; text-decoration:none; overflow:hidden;color:#545454}
 #Nav_left h1 a:hover{ color:#f77801;}
  #Nav_left h1.Navleft1 a{color:#f77801;background:url(../images/jia1.png) no-repeat   30px center}
 
 #Nav_left .no {display:none;}
 #Nav_left .h1 a{color:#333;}
  #Nav_left ul { padding-left:60px; overflow:auto;border-bottom:1px solid #e3e3e3}
  #Nav_left ul li {height:30px;line-height:30px}
 #Nav_left ul li a{background:url(../images/dotted.jpg) no-repeat  left center;line-height:30px;padding-left:10px}
 #Nav_left ul li a:hover{color:#f77801;background:url(../images/dottedred.jpg) no-repeat  left center;}
 

<div id="Nav_left">
 <h1 onClick="javascript:ShowMenu(this,0)" ><a href="javascript:void(0)" >一级菜单A</a></h1>
 <span class="no">
 <ul>
 <li><a href="">一级菜单A_1</a></li>
 <li><a href="">一级菜单A_1</a></li>
 </ul>
 </span>
  <h1 onClick="javascript:ShowMenu(this,1)"><a href="javascript:void(0)">一级菜单A</a></h1>
   <span class="no">
  <ul>
 <li><a href="">一级菜单A_1</a></li>
 <li><a href="">一级菜单A_1</a></li>
 </ul>
 </span>
</div>

<!DOCTYPE html> 
<html> 
<head> 
<meta charset="utf-8" /> 
<title>无限级折叠菜单 1.01 JS版</title> 
<meta name="keywords" content="hj1227 原创无限级折叠菜单 1.01js版"> 
<meta name="description" content="hj1227 原创无限级折叠菜单 1.01js版"> 
<style> 
<!-- 
body,ul,h3 {margin:0px; padding:0px;} 
li {list-style-type:none;} 
body{ 
font-size:12px; 
color:#333; 
font-family: Simsun; 
line-height:15px; 
} 
a{text-decoration:none;color:#004285;border:none;} 
a:hover{text-decoration:none;color:#C33;} 
#menu { 
width:260px; 
margin:50px auto; 
padding:10px; 
border:#EEE 1px solid; 
} 
#menu h3 { 
font-size:12px; 
} 
#menu ul { 
background:url("http://demo.jb51.net/js/2011/caidan/ul-bg.gif") repeat-y 5px 0px; overflow:hidden; 
} 
#menu ul li { 
padding:5px 0 2px 15px; 
background:url("http://demo.jb51.net/js/2011/caidan/tree-ul-li.gif") no-repeat 5px -32px; 
} 
#menu ul li ul {display:none;} 
#menu ul li em { 
cursor:pointer; 
display:inline-block; 
width:15px; 
float:left; 
height:15px; 
margin-left:-14px; 
background:url("http://demo.jb51.net/js/2011/caidan/tree-ul-li.gif") no-repeat -32px 2px; 
} 
#menu ul li em.off { 
background-position: -17px -18px; 
} 
#menu ul li#end { 
background-color:#FFF; 
} 
#menu ul.off { 
display:block; 
} 
--> 
</style> 
</head> 
<body> 
<div id="menu"> 
<h3>无限级折叠菜单 1.0.1 JS版</h3> 

<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_1_1</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_2_1</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_3_1</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_3_2</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_2_2</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_3_1</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_3_2</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
</ul> 

</li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_1_2</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_2_1</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_3_1</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_3_2</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_2_2</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_3_1</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_3_2</a> 
<ul> 
<li><em></em><a href='javascript:void(0);'>菜单_4_1</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
<li id='end'><em></em><a href='javascript:void(0);'>菜单_4_2</a> 
<ul> 
<li><a href='javascript:void(0);'>菜单_5_1</a></li> 
<li id='end'><a href='javascript:void(0);'>菜单_5_2</a></li> 
</ul> 

</li> 
</ul> 

</li> 
</ul> 

</li> 
</ul> 

</li> 
</ul> 
</div> 
<script type="text/javascript"> 
(function(e){ 
for(var _obj=document.getElementById(e.id).getElementsByTagName(e.tag),i=-1,em;em=_obj[++i];){ 
em.onclick = function(){ //onmouseover 
var ul = this.nextSibling; 
if(!ul){return false;} 
ul = ul.nextSibling; if(!ul){return false;} 
if(e.tag != 'a'){ ul = ul.nextSibling; if(!ul){return false;} } //a 标签控制 隐藏或删除该行 
for(var _li=this.parentNode.parentNode.childNodes,n=-1,li;li=_li[++n];){ 
if(li.tagName=="LI"){ 
for(var _ul=li.childNodes,t=-1,$ul;$ul=_ul[++t];){ 
switch($ul.tagName){ 
case "UL": 
$ul.className = $ul!=ul?"" : ul.className?"":"off"; 
break; 
case "EM": 
$ul.className = $ul!=this?"" : this.className?"":"off"; 
break; 
} 
} 
} 
} 
} 
} 
})({id:'menu',tag:'em'}); 
</script> 
</body> 
</html>