/* keyboard interface: use cursor-keys to switch background-images */
document.onkeydown = function(e)
{
  var element = null;
  switch(e.which)
  {
    case 37:
      //prevImage();
      element = document.getElementById("left_arrow");
      if(element)
        location.replace(element.href);
    break;
    case 39:
      //nextImage();
      element = document.getElementById("right_arrow");
      if(element)
        location.replace(element.href);
    break;
    case 27:
      location.replace(".");
      return false;
    break;
  }
}