function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		nav_home_over = newImage("images/nav_home_over.gif");
		nav_company_over = newImage("images/nav_company_over.gif");
		nav_frasco_over = newImage("images/nav_frasco_over.gif");
		nav_practiceprofit_over = newImage("images/nav_practiceprofit_over.gif");
		nav_products_over = newImage("images/nav_products_over.gif");
		nav_casting_over = newImage("images/nav_casting_over.gif");
		nav_orderform_over = newImage("images/nav_orderform_over.gif");
		nav_offer_over = newImage("images/nav_offer_over.gif");
		nav_newsletter_over = newImage("images/nav_newsletter_over.gif");
		nav_contactus_over = newImage("images/nav_contactus_over.gif");
		preloadFlag = true;
	}
}