var gallerylinks;

function showPic (whichpic) {
  if (!document.getElementById) return true;
  document.getElementById('placeholder').src = whichpic.href;
  whichpic.className="selected";
  for ( var i=0; i < gallerylinks.length; i++) {
    if (gallerylinks[i] != whichpic) { gallerylinks[i].className=""; }
  }
  return false;
}

function prepareGallery() {
  if (!document.getElementsByTagName) return false;
  if (!document.getElementById) return false;
  if (!document.getElementById("gallery")) return false;
  var gallery = document.getElementById("gallery");
  gallerylinks = gallery.getElementsByTagName("a");
  for ( var i=0; i < gallerylinks.length; i++) {
    gallerylinks[i].onmouseover = function() { return showPic(this); }
  }
  showPic(gallerylinks[0]);
}

window.onload=prepareGallery;