Javascript: self.resizeTo() bug IE

var Fenetre=new Object();
Fenetre.Height=null;
Fenetre.Width=null;
var x = null;
var y = null;
var x2 = null;
var y2 = null;
var Height=null;
var Width=null;
	
window.onload=function(){
Fenetre.Height=screen.height-50;
Fenetre.Width=screen.width-50;
Height=Fenetre.Height;
Width=Fenetre.Width;
self.resizeTo(Fenetre.Width,Fenetre.Height);
}

function DownAcResize(Obj,e){
x = (navigator.appName.substring(0,3) == "Net") ? e.pageX : event.x+document.body.scrollLeft;
y = (navigator.appName.substring(0,3) == "Net") ? e.pageY : event.y+document.body.scrollTop;

}

function MoveAcResize(Obj,e){

	if(x!=null){	
		
	// position de la souri	
	x2 = (navigator.appName.substring(0,3) == "Net") ? e.pageX : event.x+document.body.scrollLeft;
	y2 = (navigator.appName.substring(0,3) == "Net") ? e.pageY : event.y+document.body.scrollTop;
	
	var xF=x-x2;
	var yF=y-y2;
	
	Height=Fenetre.Height-yF;
	Width=Fenetre.Width-xF;
	
	}
	self.resizeTo(Width,Height);
}

function UpAcResize(Obj,e){
	x=null;
}

<div id="resizeWindow" 
             onmousedown="DownAcResize(this,event);" 
             onmousemove="MoveAcResize(this,event);"
             onmouseup="UpAcResize(this,event);"
             onmouseout="UpAcResize(this,event);">
        </div>