function setSize(){
	var breite=0;
	var hoehe=0;
	if(navigator.userAgent.indexOf("MSIE")<0){
	    breite=window.innerWidth;
	    hoehe=window.innerHeight;
	}
	else{
	    breite=document.documentElement.clientWidth;
	    hoehe=document.documentElement.clientHeight; 
	}
	if(breite<940){
		document.getElementById("hintergrund").style.left="0px";
		document.getElementById("hintergrund").style.marginLeft="0px";
	}else{
		document.getElementById("hintergrund").style.left="50%";
		document.getElementById("hintergrund").style.marginLeft="-470px";
	}
	if(hoehe<610){
		document.getElementById("hintergrund").style.top="0px";
		document.getElementById("hintergrund").style.marginTop="0px";
	}else{
		document.getElementById("hintergrund").style.top="50%";
		document.getElementById("hintergrund").style.marginTop="-305px";
	}
    }