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) {
		office_over = newImage("img/common/office-over.gif");
		profile_over = newImage("img/common/profile-over.gif");
		seminar_over = newImage("img/common/seminar-over.gif");
		toiawase_over = newImage("img/common/toiawase-over.gif");
		tabi_over = newImage("img/common/tabi-over.gif");
		tclinic_over = newImage("img/common/t-clinic-over.gif");
		kenshoku_over = newImage("img/common/k-tsuhando-over.gif");
		toppage_over = newImage("img/common/top-over.gif");
		preloadFlag = true;
	}
}