function pop(b,w,h) {
  gross = window.open("/bild.php?w="+w+"&h="+h+"&u="+b, "grossansicht", "height="+h+",width="+w+",left="+screen.availWidth/2-w/2+"top="+screen.availHeight/2-h/2+"scrollbars=no,status=no,toolbar=no,menubar=no,location=no");
  gross.resizeTo(w,h);
  gross.focus();
}