/** Changes the source of an image element
	@param string id The id of the image element
	@param string imageName The name of the image file without the path or extension
	@param bool isOver Whether or not the mouse is over the image element
*/
function swapNavImage (id,imageName, isOver) 
{
	img = getObject (id);
	if (img) {
		imagePath = "../images/nav/" + imageName
		
		if (isOver) {
			imagePath = imagePath + "-over";
		}
		
		imagePath = imagePath + ".jpg";				
		img.src = imagePath;
	}
}

function purchaseOnline()
{
	window.open ('../shop_popup.php', 'shop', 'height=200,width=300');	
}
/** Retrieve the object with the given ID
 *	@param string objectID The ID of the object.
 *	@return [object] The object or null if not found
 */
function getObject(objectId) {
    // cross-browser function to get an object's style object given its id
    if(document.getElementById && document.getElementById(objectId)) {
		// W3C DOM
		return document.getElementById(objectId);
    } 
	else if (document.all && document.all(objectId)) 
	{
		// MSIE 4 DOM
		return document.all(objectId);
    } 
	else if (document.layers && document.layers[objectId]) 
	{
		// NN 4 DOM.. note: this won't find nested layers
		return document.layers[objectId];
    } else 
	{
		return false;
    }
} // getObject