function wechsel(url,bildname) {
           window.document.images[bildname].src = url;
        }


        var popUpWin=0;
        function popUpWindow(URLStr, left, top, width, height)
        {
          if(popUpWin)
          {
            if(!popUpWin.closed) popUpWin.close();
          }
          popUpWin = open(URLStr, 'popUpWin', 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=no,copyhistory=yes,width='+width+',height='+height+',left='+left+', top='+top+',screenX='+left+',screenY='+top+'');
        }