纯css实现多级折叠菜单折叠树效果

<ol class="tree">  
       <li>  
           <label for="folder1" class="folderOne">泽元框架</label> <input type="checkbox" id="folder1" /> 
           <ol>  
                <li>  
                   <label for="subfolder1"class="folderTwo">开发规范</label> <input type="checkbox" id="subfolder1"  />   
                   <ol>  
                       <li class="file folderThree"><a href="#">常见界面错误举例</a></li>  
                       <li class="file folderThree"><a href="#">关于发行报告对BUG管理提出…</a></li>  
                       <li class="file folderThree"><a href="#">插件内部JAVA包命名规范</a></li>  
                   </ol>  
               </li> 
                <li class="file folderTwo"><a href="#">概述</a></li>  
                <li class="file folderTwo"><a href="#">服务器集群</a></li>  
                <li class="file folderTwo"><a href="#">模板</a></li>  
                <li class="file folderTwo"><a href="#">安全机制</a></li>   
           </ol>  
  
       </li>  
       <li>  
           <label for="folder2" class="folderOne" >ZCMS</label> <input type="checkbox" id="folder2" />   
           <ol>  
               <li class="file folderTwo"><a href="#">实时数据</a></li> 
               <li>  
                   <label for="subfolder2" class="folderTwo">实时数据</label> <input type="checkbox" id="subfolder2"  />   
                   <ol>  
                       <li class="file folderThree"><a href="#">实时数据</a></li>  
                       <li class="file folderThree"><a href="#">实时数据</a></li>  
                       <li class="file folderThree"><a href="#">实时数据</a></li>  
                   </ol>  
               </li>  
           </ol>  
       </li> 
       <li>  
           <label for="folder3"  class="folderOne">ZAS</label> <input type="checkbox" id="folder3" />   
           <ol>  
               <li class="file folderTwo"><a href="#">实时数据</a></li> 
               <li class="file folderTwo"><a href="#">实时数据</a></li> 
           </ol>  
       </li> 
       <li>  
           <label for="folder4"  class="folderOne">ZHTML标签</label> <input type="checkbox" id="folder4"/>   
           <ol>  
               <li class="file folderTwo"><a href="#">实时数据</a></li> 
               <li class="file folderTwo"><a href="#">实时数据</a></li> 
           </ol>  
       </li> 
       <li>  
           <label for="folder5"  class="folderOne">UI框架API手册</label> <input type="checkbox" id="folder5"/>   
           <ol>  
               <li class="file folderTwo"><a href="#">实时数据</a></li> 
               <li class="file folderTwo"><a href="#">实时数据</a></li> 
           </ol>  
       </li> 
   </ol>

<style type="text/css">  
    .tree {margin: 0;padding: 0;background-color:#f2f2f2;overflow: hidden;}  
    /*隐藏input*/
    .tree li input{position: absolute;left: 0;opacity: 0;z-index: 2;cursor: pointer;height: 1em;width:1em;top: 0;}  
    /*所有菜单项设置统一样式*/
    .tree li {position: relative;list-style: none;}   
    /*一级菜单加下边线*/
    .tree>li{border-bottom: 1px solid #d9d9d9;}
    /*给有子菜单的菜单项添加背景图标*/
    .tree li label {max-width:999px;cursor: pointer;display: block;margin:0 0 0 -50px;padding: 15px 10px 15px 70px;background: url(../../images/cp-detail-arrow-b.png) no-repeat right center;background-position:95% 50%;white-space:nowrap;overflow:hidden;text-overflow: ellipsis; }  
    .tree li label:hover,li label:focus{background-color:#a7a7a7;color:#fff;}
    /*清除所有展开的子菜单的display*/
    .tree li input + ol{display: none;}  
    /*当input被选中时，给所有展开的子菜单设置样式*/
    .tree input:checked + ol {padding-left:14px;height: auto;display: block;}  
    .tree input:checked + ol > li { height: auto;}  
    /*末层菜单为A标签，设置样式*/
    .tree li.file a{margin:0 -10px 0 -50px;padding: 15px 20px 15px 70px;text-decoration:none;display: block;color:#333333;white-space:nowrap;overflow:hidden;text-overflow: ellipsis;} 
    .tree li.file a:hover,li.file a:focus{background-color:#a7a7a7;color:#fff;} 
    /*不同层级的菜单字体大小不同*/
    .tree .folderOne{font-size: 18px;}
    .tree .folderTwo{font-size:16px;}
    .tree .folderThree{font-size:14px;}
</style>

<script type="text/javascript">
       $(document).ready(function() {
           //每个有子菜单的菜单项添加点击事件
           $(".tree label").click(function(){
               //获取当前菜单旁边input的check状态
               var isChecked = $(this).next("input[type='checkbox']").is(':checked');
               //展开和收齐的不同状态下更换右侧小图标
               if(isChecked){
                   $(this).css(
                       "background-image","url(../images/cp-detail-arrow-b.png)"
                   );
               }else{
                   $(this).css(
                       "background-image","url(../images/cp-detail-arrow-t.png)"
                   );
               }
           });
            
       });
   </script>

<div>业务管理<span></span></div>
<ul>
...
<ul>

<div class="collapsed">汇总分析<span></span></</div>
<ul>
...
<ul>

<div class="collapsed"系统管理<span></span></</div>
<ul>
...
<ul>

div span { float:right; padding-right:20px; }
div span:after { content: "∨" }
div.collapsed span:after { content: "∧" }

div.collapsed + ul { height: 0px; transition: height 0.5s ease-out; }
div ul { height: 80px; transition: height 0.5s ease-in; }