function popup(adresse, beschreibung, W, H, center) {
	
	var left, top, desc, param;
	W = 470;
	H = 490;
	
	if(center == 1) {
		left	=	(screen.width)	?	(screen.width-W)/2:100;
		top		=	(screen.height)	?	(screen.height-H)/2:100;
	}
	else { 
		left 	= 400;
		top		= 50;
	}

	desc = "'" + beschreibung + "'";

	param += "'dependent=yes, location=no, menubar=0, scrollbars=no, status=no, toolbar=no, resizable=no, top=" + top + ", left=" + left + ", width=" 	+ W + ", height=" + H +	"'";
	
	fenster = window.open (adresse, beschreibung, param);
	fenster.focus;
}