function showPic(whichpic) {
  if (!document.getElementById("placeholder")) return true;
  var source = whichpic.getAttribute("href");
  
  var nav = document.getElementById(source.split("#")[1]);
  var links = nav.getElementsByTagName("img");
  for (var i=0; i<links.length; i++ ) {
    var source = links[i].getAttribute("src");
   }
  
  
  
  var placeholder = document.getElementById("placeholder");
  placeholder.setAttribute("src",source);
  if (!document.getElementById("description")) return false;
  return false;
}

function preparePlaceholder() {
  if (!document.createElement) return false;
  if (!document.createTextNode) return false;
  if (!document.getElementById) return false;
  if (!document.getElementById("imagegallery")) return false;
  var placeholder = document.createElement("img");
  placeholder.setAttribute("id","placeholder");
  placeholder.setAttribute("src","images/placeholder.gif");
  placeholder.setAttribute("alt","my image gallery");
  var description = document.createElement("p");
  description.setAttribute("id","description");
  var desctext = document.createTextNode("Choose an image");
  description.appendChild(desctext);
  var gallery = document.getElementById("imagegallery");
  insertAfter(description,gallery);
  insertAfter(placeholder,description);
}

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

addLoadEvent(preparePlaceholder);
addLoadEvent(prepareGallery);