function imgFade(id, delay)
{
  if (!imgFade.timer)
  {
    imgFade.index = -1;
    imgFade.nodes = document.getElementById(id).getElementsByTagName('img');
    imgFade.timer = setInterval(imgFade, delay);
  }

  if (imgFade.index != -1)
    imgFade.nodes[imgFade.index].style.opacity = 0;

  if (++imgFade.index >= imgFade.nodes.length)
    imgFade.index = 0;

  imgFade.nodes[imgFade.index].style.opacity = 1;
}