function bild(dateiname)
{
    var hori = screen.availWidth;
    var verti = screen.availHeight;
    var w=850;
    var h=700;
	{
	window.open(dateiname, 'Bildergalerie', 'toolbar=no,location=no,directories=no,status=yes,menubar=no,scrollbars=yes,resizable=yes,copyhistory=no,width='+ w  +',height='+ h +',left='+((hori - w- 10)* .5) +',top='+((verti - h- 30)* .5))
	window.focus;
	}
}