/**
 * Swaps the header image randomly each page load
 */
function swapHeader() {
	
	// Generate random number
	var random = Math.ceil((Math.random() * 6));
	
	// Add the random class to the header logo. The style sheet should have a matching definition
	$('header-logo').addClassName('logo-' + random);
}

Event.observe(window, 'load', swapHeader);