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) {
		shop_over = newImage("images/menu_under/shop-over.gif");
		school_over = newImage("images/menu_under/school-over.gif");
		biyou_over = newImage("images/menu_under/biyou-over.gif");
		salon_over = newImage("images/menu_under/salon-over.gif");
		yoyaku_over = newImage("images/menu_under/yoyaku-over.gif");
		toiawase_over = newImage("images/menu_under/toiawase-over.gif");
		link_over = newImage("images/menu_under/link-over.gif");
		preloadFlag = true;
	}
}