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) {
		id1st_Class_top_03_over = newImage("images/1st_Class_top_03-over.jpg");
		id1st_Class_top_05_over = newImage("images/1st_Class_top_05-over.jpg");
		id1st_Class_top_07_over = newImage("images/1st_Class_top_07-over.jpg");
		id1st_Class_top_09_over = newImage("images/1st_Class_top_09-over.jpg");
		id1st_Class_top_18_over = newImage("images/1st_Class_top_18-over.jpg");
		id1st_Class_top_21_over = newImage("images/1st_Class_top_21-over.jpg");
		id1st_Class_top_23_over = newImage("images/1st_Class_top_23-over.jpg");
		id1st_Class_top_25_over = newImage("images/1st_Class_top_25-over.jpg");
		id1st_Class_top_27_over = newImage("images/1st_Class_top_27-over.jpg");
		id1st_Class_top_29_over = newImage("images/1st_Class_top_29-over.jpg");
		id1st_Class_top_31_over = newImage("images/1st_Class_top_31-over.jpg");
		preloadFlag = true;
	}
}