var drag={
    "obj":null,
	"init":function(handle, dragbody, e){
		if (e == null) {
			handle.onmousedown=drag.start;
		}
		handle.root = dragbody;

		if(isnan(parseint(handle.root.style.left)))handle.root.style.left="0px";
		if(isnan(parseint(handle.root.style.top)))handle.root.style.top="0px";
		handle.root.ondragstart=new function();
		handle.root.ondragend=new function();
		handle.root.ondrag=new function();
		if (e !=null) {
			var handle=drag.obj=handle;
			e=drag.fixe(e);
			var top=parseint(handle.root.style.top);
			var left=parseint(handle.root.style.left);
			handle.root.ondragstart(left,top,e.pagex,e.pagey);
			handle.lastmousex=e.pagex;
			handle.lastmousey=e.pagey;
			document.onmousemove=drag.drag;
			document.onmouseup=drag.end;
		}
	},
	"start":function(e){
		var handle=drag.obj=this;
		e=drag.fixevent(e);
		var top=parseint(handle.root.style.top);
		var left=parseint(handle.root.style.left);
		//alert(left)
		handle.root.ondragstart(left,top,e.pagex,e.pagey);
		handle.lastmousex=e.pagex;
		handle.lastmousey=e.pagey;
		document.onmousemove=drag.drag;
		document.onmouseup=drag.end;
		return false;
	},
	"drag":function(e){
		e=drag.fixevent(e);
							
		var handle=drag.obj;
		var mousey=e.pagey;
		var mousex=e.pagex;
		var top=parseint(handle.root.style.top);
		var left=parseint(handle.root.style.left);
		
		if(document.all){drag.obj.setcapture();}else{e.preventdefault();};//作用是将所有鼠标事件捕获到handle对象，对于firefox，以用preventdefault来取消事件的默认动作：

		var currentleft,currenttop;
		currentleft=left+mousex-handle.lastmousex;
		currenttop=top+(mousey-handle.lastmousey);
		handle.root.style.left=currentleft +"px";
		handle.root.style.top=currenttop+"px";
		handle.lastmousex=mousex;
		handle.lastmousey=mousey;
		handle.root.ondrag(currentleft,currenttop,e.pagex,e.pagey);
		return false;
	},
	"end":function(){
		if(document.all){drag.obj.releasecapture();};//取消所有鼠标事件捕获到handle对象
		document.onmousemove=null;
		document.onmouseup=null;
		drag.obj.root.ondragend(parseint(drag.obj.root.style.left),parseint(drag.obj.root.style.top));
		drag.obj=null;
	},
	"fixevent":function(e){//格式化事件参数对象
		var sl = math.max(document.documentelement.scrollleft, document.body.scrollleft);
		var st = math.max(document.documentelement.scrolltop, document.body.scrolltop);
		if(typeof e=="undefined")e=window.event;
		if(typeof e.layerx=="undefined")e.layerx=e.offsetx;
		if(typeof e.layery=="undefined")e.layery=e.offsety;
		if(typeof e.pagex == "undefined")e.pagex = e.clientx + sl - document.body.clientleft;
		if(typeof e.pagey == "undefined")e.pagey = e.clienty + st - document.body.clienttop;
		return e;
	}
};