最精简的JavaScript鼠标拖动代码

var drag_=falsevar D=new Function('obj','return document.getElementById(obj);')var oevent=new Function('e','if (!e) e = window.event;return e')function Move_obj(obj){    var x,y;    D(obj).onmousedown=function(e){        drag_=true;        with(this){            style.position="absolute";var temp1=offsetLeft;var temp2=offsetTop;            x=oevent(e).clientX;y=oevent(e).clientY;            document.onmousemove=function(e){                if(!drag_)return false;                with(this){                    style.left=temp1+oevent(e).clientX-x+"px";                    style.top=temp2+oevent(e).clientY-y+"px";                }            }        }        document.onmouseup=new Function("drag_=false");    }}