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) {
		main_navi_01_over = newImage("images/main_navi_01-over.gif");
		main_navi_02_main_navi_01_over = newImage("images/main_navi_02-main_navi_01_o.gif");
		main_navi_03_main_navi_01_over = newImage("images/main_navi_03-main_navi_01_o.gif");
		main_navi_04_main_navi_01_over = newImage("images/main_navi_04-main_navi_01_o.gif");
		main_navi_05_main_navi_01_over = newImage("images/main_navi_05-main_navi_01_o.gif");
		preloadFlag = true;
	}
}