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) {
		index_01_btn_viewcart_over = newImage("images/index_01-btn_viewcart_over.jpg");
		btn_viewcart_over = newImage("images/btn_viewcart-over.jpg");
		btn_checkout_over = newImage("images/btn_checkout-over.jpg");
		btn_home_over = newImage("images/btn_home-over.jpg");
		btn_books_over = newImage("images/btn_books-over.jpg");
		btn_news_over = newImage("images/btn_news-over.jpg");
		btn_press_over = newImage("images/btn_press-over.jpg");
		btn_catalog_over = newImage("images/btn_catalog-over.jpg");
		btn_email_over = newImage("images/btn_email-over.jpg");
		btn_links_over = newImage("images/btn_links-over.jpg");
		btn_contact_over = newImage("images/btn_contact-over.jpg");
		btn_search_over = newImage("images/btn_search-over.jpg");
		preloadFlag = true;
	}
}

function clearDefault(el) {
  if (el.defaultValue==el.value) el.value = ""
}