function fenster(url, width, height, x, y)
{
	if (x == 0 && y == 0)
	{
	       var x1=((screen.width/2)-(width/2));
	       var y1=((screen.height/2)-(height/2));

	       var x=Math.round (x1);
	       var y=Math.round (y1);
	}

	var name =navigator.appName;
	var plattform=navigator.platform;


       if (name == "Microsoft Internet Explorer" || plattform == "MacPPC")
       {
       	    var win=window.open (url,"ngi","Width=" + width + ",Height=" + height + ",menubar=0,scrollbars=0,toolbar=0,location=0,directories=0,status=0");
       	    win.moveTo (x,y);
       }


       else
       {
            var win=window.open (url,"pauwau","Width=" + width + ",Height=" + height + ",menubar=0,scrollbars=0,toolbar=0,location=0,directories=0,status=0,resizeable=0");
            win.moveTo (x,y);
       }
}