function popup(url, breite, hoehe) {
	links = (screen.width/2)-(breite/2);
	oben = (screen.height/2)-(hoehe/2);
	window.open(url,"popup","height="+hoehe+",width="+breite+",status = no,toolbar = no,menubar = yes,location = no,resizable = no,titlebar = no,scrollbars = yes,fullscreen = no,top ="+oben+",left ="+links);
}