function imagePreview(image_file, height, width)
  {
    if (image_file.indexOf("/") < 0)
      image_file = '/img/preview/preview/' + image_file + '.png';

    window.open(image_file, '', 'left=' + (screen.width - width)/2 + ',top=' + (screen.height - height - 20)/2 + ',location=no,menubar=no,resizable=no,status=no,toolbar=no,height=' + height + ',width=' + width + ',innerHeight=' + height + ',innerWidth=' + width);
    return false;
  }

  function addSmile(smile)
  {
    document.getElementsByName('form[comment]')[0].value = document.getElementsByName('form[comment]')[0].value + smile;
  }