移动DIV的有关问题？

移动DIV的问题？？？
下面的DIV移动起来为什么很困难？
请问还有什么移动DIV的方法吗？

HTML code

<SCRIPT LANGUAGE="JavaScript"><!--var oldX=0,oldY=0;var isDrag = false;function init(){    isDrag=true;    oldX=window.event.x;    oldY=window.event.y;}function end(){    isDrag=false;}function moveIt(obj){    if(isDrag){    var x =window.event.x;    var y = window.event.y;    obj.style.left = parseInt(obj.style.left.replace("px","")) + (x - oldX);    obj.style.top = parseInt(obj.style.top.replace("px","")) + (y - oldY);    oldX = x;    oldY = y;    }}//--></SCRIPT><div id="wnd" onMouseDown="init();" onMouseMove="moveIt(this);" onMouseUp="end();" style="border:1px outset #333333;position:absolute;filter:alpha(opacity=70);top:100;left:200;width:200;height:120;display:inline;"></div>

JScript code

var dragapproved=false; function drag() {    if(!document.all)    {       return;    }    if(event.srcElement.className=="myClass")    {       dragapproved=true;       var obj=event.srcElement;       var tempX=obj.style.pixelLeft;       var tempY=obj.style.pixelTop;       var x=event.clientX;       var y=event.clientY;       document.onmousemove=move;       function move()       {          if(event.button==1 && dragapproved)          {             obj.style.pixelLeft=tempX+event.clientX-x;             obj.style.pixelTop=tempY+event.clientY-y;             return false;          }       }    } } document.onmousedown=drag; document.onmouseup=new Function("dragapproved=false");