<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css"> 
 *{ margin:0; padding:0; list-style:none;} 
 body { margin:20px;} 
 h2 { font-family:"黑体"; font-size:24px; text-align:center; line-height:32px;} 
 h5 { font-size:12px; text-align:center; font-weight:normal; color:#666; line-height:28px;} 
 #nav a { text-decoration:underline;color:#06c; font-size:14px; line-height:24px;} 
 #nav ul{ margin-bottom:5px;} 
 #nav strong{ color:#696;} 
 #nav.dyn li ul{ display:none;} 
 #nav.dyn li ul.show{ display:block;} 
 #nav.dyn li{ padding-left:15px;} 
 #nav.dyn li.parent{ background:url(images/user_23.gif) 5px 10px no-repeat;} 
 #nav.dyn li.open{ background:url(images/user_23.gif) 5px -34px no-repeat;} 
 </style> 
<script type="text/javascript">
DOMhelp={
 debugWindowId:'DOMhelpdebug',
 init:function(){
  if(!document.getElementById || !document.createTextNode){return;}
 },
 lastSibling:function(node){
  var tempObj=node.parentNode.lastChild;
  while(tempObj.nodeType!=1 && tempObj.previousSibling!=null){
   tempObj=tempObj.previousSibling;
  }
  return (tempObj.nodeType==1)"text/javascript"> 
<!-- 
sn={ 
 dynamicClass:'dyn', 
 showClass:'show', 
 parentClass:'parent', 
 openClass:'open', 
 navID:'nav', 
 init:function(){ 
 var triggerLink; 
 if(!document.getElementById || !document.createTextNode){return;} 
 var nav=document.getElementById(sn.navID); 
 if(!nav){return;} 
 DOMhelp.cssjs('add',nav,sn.dynamicClass);  
 var nested=nav.getElementsByTagName('ul'); 
 for(var i=0;i<nested.length;i++){ 
  triggerLink=nested[i].parentNode.getElementsByTagName('a')[0]; 
  DOMhelp.cssjs('add',triggerLink.parentNode,sn.parentClass);  
  DOMhelp.addEvent(triggerLink,'click',sn.changeSection,false); 
  triggerLink.onclick=DOMhelp.safariClickFix; 
  if(nested[i].parentNode.getElementsByTagName('strong').length>0){ 
  DOMhelp.cssjs('add',triggerLink.parentNode,sn.openClass);  
  DOMhelp.cssjs('add',nested[i],sn.showClass); 
  } 
 } 
 }, 
 changeSection:function(e){ 
 var t=DOMhelp.getTarget(e); 
 var firstList=t.parentNode.getElementsByTagName('ul')[0]; 
 if(DOMhelp.cssjs('check',firstList,sn.showClass)){ 
  DOMhelp.cssjs('remove',firstList,sn.showClass) 
  DOMhelp.cssjs('swap',t.parentNode,sn.openClass,sn.parentClass); 
 } else { 
  DOMhelp.cssjs('add',firstList,sn.showClass) 
  DOMhelp.cssjs('swap',t.parentNode,sn.openClass,sn.parentClass); 
 } 
 DOMhelp.cancelClick(e); 
 } 
} 
DOMhelp.addEvent(window,'load',sn.init,false); 
--> 
</script> 
<h2>js实现无限级树形导航列表</h2>
<ul id="nav"> 
 <li><a href="#">主页</a></li> 
 <li><a href="#">产品</a> 
 <ul> 
  <li><a href="#">大类别一</a> 
  <ul> 
   <li><a href="#">小类别一</a> 
   <ul> 
    <li><a href="#">次类别一</a></li> 
    <li><a href="#">次类别二</a></li> 
   </ul> 
   </li> 
   <li><a href="#">小类别二</a></li> 
  </ul> 
  </li> 
  <li><a href="#">大类别二</a></li> 
  <li><a href="#">大类别三</a> 
  <ul> 
   <li><a href="#">小类别一</a></li> 
   <li><a href="#">小类别二</a></li> 
  </ul> 
  </li> 
 </ul> 
 </li> 
 <li><a href="#">服务</a> 
 <ul> 
  <li><a href="#">大类别一</a></li> 
  <li><a href="#">大类别二</a></li> 
  <li><a href="#">大类别三</a></li> 
 </ul> 
 </li> 
 <li><a href="#">合作</a></li> 
 <li><a href="#">关于我们</a> 
 <ul> 
  <li><a href="#">大类别一</a> 
  <ul> 
   <li><a href="#">小类别一</a></li> 
   <li><a href="#">小类别二</a></li> 
  </ul> 
  </li> 
  <li><a href="#">大类别二</a> 
  <ul> 
   <li><a href="#">小类别一</a></li> 
   <li><a href="#">小类别二</a></li> 
  </ul> 
  </li> 
  <li><a href="#">大类别三</a> 
  <ul> 
   <li><a href="#">小类别一</a></li> 
   <li><a href="#">小类别二</a></li> 
  </ul> 
  </li> 
  <li><a href="#">大类别四</a></li> 
 </ul> 
 </li> 
 <li><a href="#">联系我们</a> 
 <ul> 
  <li><a href="#">大类别一</a></li> 
  <li><a href="#">大类别二</a></li> 
 </ul> 
 </li> 
</ul>