function twPopup(breite, hoehe, url) {
		var positionX=((screen.availWidth / 2) - breite / 2);
		var positionY=((screen.availHeight / 2) - hoehe / 2);
		
		pop=window.open(url,
		                '', 
										'toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=1,resizable=1,fullscreen=0,width='+breite+',height='+hoehe+',top='+positionY+',left='+positionX);
		/*pop.resizeTo(breite,hoehe);*/
		/*pop.moveTo(positionX,positionY);*/
		/*pop.location=url;*/
		pop.focus();
		return false;
	}