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_khbk_over = newImage("images/main-khbk_over.gif");
		main_grpk_over = newImage("images/main-grpk_over.gif");
		main_bkmn_over = newImage("images/main-bkmn_over.gif");
		main_rswh_over = newImage("images/main-rswh_over.gif");
		main_prgr_over = newImage("images/main-prgr_over.gif");
		preloadFlag = true;
	}
}