js实现无限级树形导航列表效果代码

<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)?tempObj:false; }, firstSibling:function(node){  var tempObj=node.parentNode.firstChild;  while(tempObj.nodeType!=1 && tempObj.nextSibling!=null){   tempObj=tempObj.nextSibling;  }  return (tempObj.nodeType==1)?tempObj:false; }, getText:function(node){  if(!node.hasChildNodes()){return false;}  var reg=/^/s+$/;  var tempObj=node.firstChild;  while(tempObj.nodeType!=3 && tempObj.nextSibling!=null || reg.test(tempObj.nodeValue)){   tempObj=tempObj.nextSibling;  }  return tempObj.nodeType==3?tempObj.nodeValue:false; }, setText:function(node,txt){  if(!node.hasChildNodes()){return false;}  var reg=/^/s+$/;  var tempObj=node.firstChild;  while(tempObj.nodeType!=3 && tempObj.nextSibling!=null || reg.test(tempObj.nodeValue)){   tempObj=tempObj.nextSibling;  }  if(tempObj.nodeType==3){tempObj.nodeValue=txt}else{return false;} }, createLink:function(to,txt){  var tempObj=document.createElement('a');  tempObj.appendChild(document.createTextNode(txt));  tempObj.setAttribute('href',to);  return tempObj; }, createTextElm:function(elm,txt){  var tempObj=document.createElement(elm);  tempObj.appendChild(document.createTextNode(txt));  return tempObj; }, closestSibling:function(node,direction){  var tempObj;  if(direction==-1 && node.previousSibling!=null){   tempObj=node.previousSibling;   while(tempObj.nodeType!=1 && tempObj.previousSibling!=null){     tempObj=tempObj.previousSibling;   }  }else if(direction==1 && node.nextSibling!=null){   tempObj=node.nextSibling;   while(tempObj.nodeType!=1 && tempObj.nextSibling!=null){     tempObj=tempObj.nextSibling;   }  }  return tempObj.nodeType==1?tempObj:false; }, initDebug:function(){  if(DOMhelp.debug){DOMhelp.stopDebug();}  DOMhelp.debug=document.createElement('div');  DOMhelp.debug.setAttribute('id',DOMhelp.debugWindowId);  document.body.insertBefore(DOMhelp.debug,document.body.firstChild); }, setDebug:function(bug){  if(!DOMhelp.debug){DOMhelp.initDebug();}  DOMhelp.debug.innerHTML+=bug+'/n'; }, stopDebug:function(){  if(DOMhelp.debug){   DOMhelp.debug.parentNode.removeChild(DOMhelp.debug);   DOMhelp.debug=null;  } }, getKey:function(e){  if(window.event){  var key = window.event.keyCode;  } else if(e){  var key=e.keyCode;  }  return key; },/* helper methods */ getTarget:function(e){  var target = window.event ? window.event.srcElement : e ? e.target : null;  if (!target){return false;}  while(target.nodeType!=1 && target.nodeName.toLowerCase()!='body'){   target=target.parentNode;  }  return target; }, stopBubble:function(e){  if(window.event && window.event.cancelBubble){   window.event.cancelBubble = true;  }   if (e && e.stopPropagation){   e.stopPropagation();  } }, stopDefault:function(e){  if(window.event && window.event.returnValue){   window.event.returnValue = false;  }   if (e && e.preventDefault){   e.preventDefault();  } }, cancelClick:function(e){  if (window.event){   window.event.cancelBubble = true;   window.event.returnValue = false;  }  if (e && e.stopPropagation && e.preventDefault){   e.stopPropagation();   e.preventDefault();  } }, addEvent: function(elm, evType, fn, useCapture){  if (elm.addEventListener){   elm.addEventListener(evType, fn, useCapture);   return true;  } else if (elm.attachEvent) {   var r = elm.attachEvent('on' + evType, fn);   return r;  } else {   elm['on' + evType] = fn;  } }, cssjs:function(a,o,c1,c2){  switch (a){   case 'swap':    o.className=!DOMhelp.cssjs('check',o,c1)?o.className.replace(c2,c1):o.className.replace(c1,c2);   break;   case 'add':    if(!DOMhelp.cssjs('check',o,c1)){o.className+=o.className?' '+c1:c1;}   break;   case 'remove':    var rep=o.className.match(' '+c1)?' '+c1:c1;    o.className=o.className.replace(rep,'');   break;   case 'check':    var found=false;    var temparray=o.className.split(' ');    for(var i=0;i<temparray.length;i++){     if(temparray[i]==c1){found=true;}    }    return found;   break;  } }, safariClickFix:function(){ return false; }}DOMhelp.addEvent(window, 'load', DOMhelp.init, false);</script> <script type="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>