javascript实现焦点滚动图效果 具体方法

<div class="sub_box"> 
                       <div id="p-select" class="sub_nav"> 
                           <div class="sub_no" id="bd1lfsj"> 
                               <ul> 
                                   <li class="show">1</li> 
                                   <li class="">2</li> 
                                   <li class="">3</li> 
                                   <li class="">4</li> 
                                   <li class="">5</li> 
                                   <li class="">6</li> 
                                   <li class="">7</li> 
                               </ul> 
                           </div> 
                       </div> 
                       <div id="bd1lfimg"> 
                           <div> 
                               <dl class="show"> 
                               </dl> 
                               <asp:Repeater ID="repTopPicture" runat="server"> 
                                   <ItemTemplate> 
                                       <dl class=""> 
                                           <dt><a href=""> 
                                               <img src='<%#Eval("ImageUrl")%>' /></a></dt> 
                                       </dl> 
                                   </ItemTemplate> 
                               </asp:Repeater> 
                           </div> 
                       </div> 
                   </div> 
                   <script type="text/javascript">                        movec();</script> 

//选择器  
function $a(id,tag){var re=(id&&typeof id!="string")?id:document.getElementById(id);if(!tag){return re;}else{return re.getElementsByTagName(tag);}} 

//焦点滚动图 点击移动  
function movec() 
{ 
    var o=$a("bd1lfimg",""); 
    var oli=$a("bd1lfimg","dl"); 
    var oliw=oli[0].offsetWidth; //每次移动的宽度     
    var ow=o.offsetWidth-2; 
    var dnow=0; //当前位置    
    var olf=oliw-(ow-oliw+10)/2; 
        o["scrollLeft"]=olf+(dnow*oliw); 
    var rqbd=$a("bd1lfsj","ul")[0]; 
    var extime; 

    <!--for(var i=1;i<oli.length;i++){rqbd.innerHTML+="<li>"+i+"</li>";}--> 
    var rq=$a("bd1lfsj","li"); 
    for(var i=0;i<rq.length;i++){reg(i);}; 
    oli[dnow].className=rq[dnow].className="show"; 
    var wwww=setInterval(uu,2000); 

    function reg(i){rq[i].onclick=function(){oli[dnow].className=rq[dnow].className="";dnow=i;oli[dnow].className=rq[dnow].className="show";mv();}} 
    function mv(){clearInterval(extime);clearInterval(wwww);extime=setInterval(bc,15);wwww=setInterval(uu,8000);} 
    function bc() 
    { 
        var ns=((dnow*oliw+olf)-o["scrollLeft"]); 
        var v=ns>0?Math.ceil(ns/10):Math.floor(ns/10); 
        o["scrollLeft"]+=v;if(v==0){clearInterval(extime);oli[dnow].className=rq[dnow].className="show";v=null;} 
    } 
    function uu() 
    { 
        if(dnow<oli.length-2) 
        { 
            oli[dnow].className=rq[dnow].className=""; 
            dnow++; 
            oli[dnow].className=rq[dnow].className="show"; 
        } 
        else{oli[dnow].className=rq[dnow].className="";dnow=0;oli[dnow].className=rq[dnow].className="show";} 
        mv(); 
    } 
    o.onmouseover=function(){clearInterval(wwww);} 
    o.onmouseout=function(){extime=setInterval(bc,15);wwww=setInterval(uu,8000);} 
}