JS控制DIV弹出层移动

<div class="title" style="cursor:move;color:#1E5494;" onmousedown="yidong('apDiv1')">系统提示！<span class="close" onclick="tips_pop()">×</span></div>

 

 

 

var yd=0;
var x=0;
var y=0;
function yidong(obj){
yd=obj;
x=document.all(yd).offsetLeft-event.x;
y=document.all(yd).offsetTop-event.y;

}
function document.onmousemove()
{
 //document.getElementById("idShow1").innerHTML =x+event.x;
 //document.getElementById("idShow2").innerHTML =y+event.y;

 //document.getElementById("idShow3").innerHTML =document.getElementById("apDiv1").offsetWidth;
 //document.getElementById("idShow4").innerHTML =document.getElementById("apDiv1").offsetHeight;
 if(yd!="0")
 {
  if(x+event.x<=document.documentElement.clientWidth-document.getElementById(yd).offsetWidth)
  {
   document.all(yd).style.pixelLeft=x+event.x;
  }
  if(y+event.y<=document.documentElement.clientHeight-document.getElementById(yd).offsetHeight)
  {
   document.all(yd).style.pixelTop=y+event.y;
  }
 }
}
function document.onmouseup(){
event.srcElement.releaseCapture();
yd=0;
}