var NAV_HOVER = new Object();

function page_init() {
	// Append a mostly hidden div to the document
	// to include preload images in
	preloader = document.createElement('DIV');
	preloader.setAttribute('id','image_preloader');

	// Add rollover effects on nav images
	nav_links = document.getElementById('nav');
	images = nav_links.getElementsByTagName('IMG');
	for (i = 0; i < images.length; i++) {
		orig = images.item(i).src;
		hover = orig.replace(/.gif/,"clr.gif");
		NAV_HOVER[orig] = hover;
		NAV_HOVER[hover] = orig;
		images.item(i).onmouseover =
		images.item(i).onmouseout = imageSwap;

		// Preload the hover image
		img = document.createElement('IMG');
		img.setAttribute('src',hover);
		preloader.appendChild(img);
	}

	// Attach the preloader div to the body.
	// This will force browsers
	document.getElementsByTagName('BODY').item(0).appendChild(preloader);
}

function imageSwap() {
    this.src = NAV_HOVER[this.src];
}
if (window.addEventListener) {
    window.addEventListener('load',page_init,false);
} else if (window.attachEvent) {
    window.attachEvent('onload',page_init);
}