function galerie_nav(total,start,perpage,urlstr)
{
  if ((urlstr.charAt(urlstr.length-1) != '?') && (urlstr.charAt(urlstr.length-1) != '&')) { urlstr=urlstr+'&'; }
  if (perpage >= total) { start=0; }
  else if (perpage >= total - start - 1) { start=total-perpage; }
  window.location.href=urlstr+"start="+start+"&perpage="+perpage+"&total="+total;
}