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) {
		menu_01 = newImage("images/menu_over_01.gif");
		menu_02 = newImage("images/menu_over_02.gif");
		menu_03 = newImage("images/menu_over_03.gif");
		menu_04 = newImage("images/menu_over_04.gif");
		menu_05 = newImage("images/menu_over_05.gif");
		menu_06 = newImage("images/menu_over_06.gif");
		preloadFlag = true;
	}
}