function popupWindow(datei,breite,hoehe) {

	x = screen.availWidth/2-breite/2;
        y = screen.availHeight/2-hoehe/2;
	window.open(datei,'','scrollbars=0,toolbar=0,location=0,directories=0,status=0,resizable=0,width='+breite+',height='+hoehe+',left='+x+',top='+y+',screenX='+x+',screenY='+y);

}