/* globals */

var imagePath ='/images/gui/'
var imagesCached = false
var dynImages = new Array()
var cachedImages = new Array()

dynImages['resultsBtn'] = new Array('results.gif', 'results_over.gif')
dynImages['registerBtn'] =  new Array('register.gif', 'register_over.gif')
dynImages['storeBtn'] =  new Array('store.gif', 'store_over.gif')
dynImages['aboutBtn'] = new Array('about.gif', 'about_over.gif')
dynImages['historyBtn'] = new Array('history.gif','history_over.gif')
dynImages['talkBtn'] = new Array('derbytalk.gif','derbytalk_over.gif')
dynImages['contactBtn'] = new Array('contact.gif','contact_over.gif')

/* image rollover functions */

function preloadImages() {
	if (document.images) {
		for (var imgName in dynImages) {
			cachedImages[imgName] = new Array()
			for (var i = 0; i < dynImages[imgName].length; i++) {
				cachedImages[imgName][i] = new Image
				cachedImages[imgName][i].src = imagePath + dynImages[imgName][i]
			}
		}	
	}
	return true
}
		
function roll_over(imgName) {
	var img, rollSrc
	img = document.images[imgName]
	if (document.images && imagesCached) {
		rollSrc = cachedImages[imgName][1].src
		img.src = rollSrc
	}
	return true
}

function roll_out(imgName) {
	var img, defaultSrc
	img = document.images[imgName]
	if (document.images && imagesCached) {
		defaultSrc = cachedImages[imgName][0].src
		img.src = defaultSrc
	}
	return true
}

function initPage () {
	imagesCached = preloadImages()
}

window.onload = initPage