一个有关选项卡的问题?
<!DOCTYPE   html   PUBLIC    "-//W3C//DTD   XHTML   1.0   Transitional//EN "    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">  
  <html   xmlns= "http://www.w3.org/1999/xhtml ">  
  <head>  
  <meta   http-equiv= "Content-Type "   content= "text/html;   charset=gb2312 "   />  
  <title> 标签示例 </title>  
  <style   type= "text/css ">  
  <!-- 
 body   {   font-size:14px;   font-family: "宋体 "} 
 ol   li   {   margin:8px} 
 #con   {   font-size:12px;   width:600px;   margin:0   auto} 
 #tags   {   height:23px;   width:400px;   margin:0;   padding:0;   margin-left:10px} 
 #tags   li   {   float:left;   margin-right:1px;   background:url(http://www.happyshow.org/sample/20061108/images/tagleft.gif)   no-repeat   left   bottom;   height:23px;   list-style-type:none} 
 #tags   li   a   {   text-decoration:none;   float:left;   background:url(http://www.happyshow.org/sample/20061108/images/tagright.gif)   no-repeat   right   bottom;   height:23px;   padding:0px   10px;   line-height:23px;   color:#999} 
 #tags   li.emptyTag   {   width:4px;   background:none} 
 #tags   li.selectTag   {   background-position:   left   top;   position:relative;   height:25px;   margin-bottom:-2px} 
 #tags   li.selectTag   a   {   background-position:   right   top;   color:#000;   height:25px;   line-height:25px;} 
 #tagContent   {   padding:1px;   background-color:#fff;   border:1px   solid   #aecbd4;width:100%;} 
 .tagContent   {   background:url(bg.gif)   repeat-x;   height:350px;   padding:10px;   color:#474747;   width:576px;   display:none} 
 #tagContent   div.selectTag{   display:block} 
 .tagFrame{ 
 background:url(bg.gif)   repeat-x; 
 } 
 -->  
  </style>  
  <SCRIPT   LANGUAGE= "JavaScript ">  
  <!-- 
 function   doClick_tab(o,n){ 
 	   o.className= "selectTag "; 
 	   var   j; 
 	   var   id; 
 	   var   e; 
 	   for(var   i=1;i <=n;i++){ 
 	         id   = "tab "+i; 
 	         j   =   document.getElementById(id); 
 	         e   =   document.getElementById( "tab_con "+i); 
 	         if(id   !=   o.id){ 
 	         	   j.className= "li "; 
 	         	   e.style.display   =    "none "; 
 	         }else{ 
 		e.style.display   =    "block "; 
 	         } 
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 	   } 
 //-->  
  </SCRIPT>  
  </head>  
  <body>  
  <div   id= "con ">  
        <ul   id= "tags ">  
              <li   class= "selectTag "   id= "tab1 ">  <a   href= "# "   onClick= "javascript:doClick_tab(this,4) "> 基本信息 </a>  </li>  
              <li   id= "tab2 ">  <a   href= "# "   onClick= "javascript:doClick_tab(this,4) "> 库存信息111111 </a>