<!DOCTYPE html>
 <html>
 <head>
 <script src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
 <meta charset=utf-8 />
 <title>js模擬select</title>
 </head>
    <style>
   *{ margin:0; padding:0;}
   li{ list-style:none;}
   body{ font:12px "宋體"; color:#666;}
   .select_down{ margin:100px auto; position:relative; width:600px; min-height:200px; height:auto!important; height:200px; border:1px solid #ccc; padding:20px; border-radius: 8px}
   .select_down dt{float:left;width:134px;position:relative;margin-right:5px;display:inline;}
   .select_down h3{color: #919191; font-size:12px;font-weight: normal;border:1px solid #e5e5e5;height:18px;background:#fbfbfb;line-height: 18px;text-indent:8px;}
   .select_down ul{width: 132px;border: 1px solid #e5e5e5;background:#fbfbfb;position: absolute;top: 18px;left: 0;
 z-index: 1;text-indent:8px;display:none;}
 .select_down ul li{height:22px;line-height: 22px;cursor:pointer;}
 .select_down ul li.hover{background:#f2f2f2;}
  .select_down dt a{background:url('http://www.dbjr.com.cn/hxh-hua/478335/o_select.jpg') no-repeat;position:absolute;width:18px;height:18px;top:1px;right:1px; }
   </style>
 <body>
   <div class="select_down" id="sel">
           <dl>
             <dt>
                 <h3>select選擇</h3>
                 <a href="javascript:;"></a>
                 <ul>
                     <li>jq的select模擬1</li>
                     <li>jq的select模擬2</li>
                     <li>jq的select模擬3</li>
                 </ul>
             </dt>
             <dt>
                 <h3>select選擇2</h3>
                 <a href="javascript:;"></a>
                 <ul>
                     <li>jq的select模擬11</li>
                     <li>jq的select模擬22</li>
                     <li>jq的select模擬31</li>
                 </ul>
             </dt>

         </dl>
 </div>
   <script>

     window.onload=function(){
     var oflink = document.getElementById('sel');
     var aDt = oflink.getElementsByTagName('dt');
     var aUl = oflink.getElementsByTagName('ul');
     var aH3= oflink.getElementsByTagName('h3');
     for(var i=0;i<aDt.length;i++){
         aDt[i].index = i;
         aDt[i].onclick = function(ev){
             var ev = ev || window.event;
             var This = this;
             for(var i=0;i<aUl.length;i++){
                 aUl[i].style.display = 'none';
             }
             aUl[this.index].style.display = 'block';
             document.onclick = function(){
                 aUl[This.index].style.display = 'none';
             };
             ev.cancelBubble = true;

         };
     }
     for(var i=0;i<aUl.length;i++){

         aUl[i].index = i;

         (function(ul){

             var iLi = ul.getElementsByTagName('li');

             for(var i=0;i<iLi.length;i++){
                 iLi[i].onmouseover = function(){
                     this.className = 'hover';
                 };
                 iLi[i].onmouseout = function(){
                     this.className = '';
                 };
                 iLi[i].onclick = function(ev){
                     var ev = ev || window.event;
                     aH3[this.parentNode.index].innerHTML = this.innerHTML;
                     ev.cancelBubble = true;
                     this.parentNode.style.display = 'none';
                 };
             }

         })(aUl[i]);
     }

 }
   </script>

 </body>
 </html>