function addListeners(e) {
	if (!document.getElementById)
		return;
	
	if (document.getElementById('Thumbs') != null) {
		
		var thumbContainer = document.getElementById('Thumbs');
		var thumbs = thumbContainer.getElementsByTagName('img');

		for (var i = 0; i < thumbs.length; i++) {
			addEvent(thumbs[i], 'click', swapImg, false);
		}
	}
}

function swapImg(e) {
	var el;
	if (window.event && window.event.srcElement)
		el = window.event.srcElement;
	if (e && e.target)
		el = e.target;
	if (!el)
		return;
	
	//get thumbnail title
	var newImg = el.src.replace(/_th.jpg/,".jpg");
	//swap full size image
	var fullSize = document.getElementById("FullSizeImg");
	fullSize.src = newImg;
	//replace description
	var description = document.getElementById('Description');
	description.firstChild.nodeValue = el.alt;
}

function addEvent(obj, evType, fn, useCapture){
  if (obj.addEventListener){
    obj.addEventListener(evType, fn, useCapture);
    return true;
  } else if (obj.attachEvent){
    var r = obj.attachEvent("on"+evType, fn);
    return r;
  } else {
    alert("Handler could not be attached");
  }
}

addEvent(window, 'load', addListeners, false);