function $(id){return document.getElementById(id);}
function JOEN(n){
document.documentElement.scroll =true;
$("mainpic").style.display="inline";
$("mainpic").style.top = "10%";
$("mainpic").style.left = (document.body.clientWidth - $("mainpic").offsetWidth)/2+"px";
$("mainpic").onmousedown=Function("Drag(this)"); //拖动层
$("pic").src = "images/roll_0_"+n+".jpg";
//背景层
var shield=document.createElement("div");
shield.id="shield";
shield.style.cssText="position:absolute;z-index:187;background:#000;filter:alpha(opacity=30);opacity:0.3;top:0;left:0;";
shield.style.width=document.body.scrollWidth+"px";
var AH=document.body.scrollHeight;
var BH=document.body.clientHeight;
if(AH<BH){shield.style.height=BH+"px";}else{shield.style.height=AH+"px";}
document.body.appendChild(shield);

onresize=function(){
   if(document.body.scrollHeight==document.body.clientHeight){
    if(document.body.scrollHeight>document.body.clientHeight){
     $("shield").style.height=document.body.clientHeight+"px";
    }else{
     $("shield").style.height=document.body.scrollHeight+"px";
    }
   }else{
    $("shield").style.height=document.body.scrollHeight+"px";
   }
   $("shield").style.width=document.body.clientWidth+"px";
   $("mainpic").style.left= document.body.scrollLeft+(document.body.clientWidth-$("mainpic").offsetWidth)/2+"px";
   $("mainpic").style.top="10%";
}
onscroll=function(){$("mainpic").style.top= document.body.scrollTop+(document.body.clientHeight-$("mainpic").offsetHeight)/2+"px";}
}

function hidden(){
if($("mainpic")){$("mainpic").style.display="none";}
if($("shield")){document.body.removeChild($("shield"));}
}

function Drag(str){
var e=window.event || arguments.callee.caller.arguments[0];
var deltaX=e.clientX-str.offsetLeft;
var deltaY=e.clientY-str.offsetTop;
var deltaH=document.body.scrollHeight;
var deltaW=document.body.scrollWidth;
var drag=true;
str.onmousemove=function(ev){
ev=ev?ev:window.event;
if(drag){
   var Y=ev.clientY-deltaY;
   var X=ev.clientX-deltaX;
   var H=deltaH-str.offsetHeight;
   var W=deltaW-str.offsetWidth;
    if(Y>0 || X>0){
     if(Y>=H){str.style.top=H+"px";}else{str.style.top=Y+"px";}
     if(X>=W){str.style.left=W+"px";}else{str.style.left=X+"px";}
    }
    if(Y<=0){str.style.top=0;}
    if(X<=0){str.style.left=0;}
    if(document.all){str.setCapture();}else{captureEvents(Event.MOUSEMOVE|Event.MOUSEUP);}
}}
str.onmouseup=function(){
drag=false;if(document.all){str.releaseCapture();}else{releaseEvents(Event.MOUSEMOVE|Event.MOUSEUP);}}
}