window.onload = function() {
	gallery();
}

function gallery() {
	
	// get thumbails div
	var thumbnailsDiv = document.getElementById('thumbnails');
	if(!thumbnailsDiv) { return; };
	
	// get thumbnail images
	var thumbnailLinks = thumbnailsDiv.getElementsByTagName('a');
	
	
	for (var i = 0; i < thumbnailLinks.length; i++) {
	
		thumbnailLinks[i].onclick = function() {
			swapPic(this);
			return false;
		}
		
				
	}
	
}

function swapPic(link) {

	var holder = document.getElementById('mainPic');
	
	var captionHolder = document.getElementById('caption');
	
	var picLink = link.getAttribute('href');
	var startNum = picLink.indexOf('_') + 1;
	var endNum = picLink.indexOf('.');
	var width = picLink.substring(startNum,endNum);
	var caption = link.getAttribute('title');
	
		
	holder.setAttribute('src', picLink);
	//holder.setAttribute('width', width);
	
	captionHolder.childNodes[0].nodeValue = caption;
	
}