button = new Array();
	rollover = new Array();
	var maxnum = 26;
	var ketsuban = 12;
	
	for (var i=0; i <= maxnum ; i++) {
		button[i] = new Image();
		rollover[i] = new Image();
		if (i<ketsuban||i>=21) {
			var num = i;
			num = "00" + num;
			num = num.substring(num.length - 2, num.length);
			button[i].src = "../images/menu/b" + num + ".gif";
			rollover[i].src = "../images/menu/b" + num + "_on.gif";
		}
	}
	
	function imageOn(imageName) {
		fileName = document[imageName].src;
		fileName = fileName.substring(0, fileName.length - 4);
		document[imageName].src = fileName + "_on.gif";
	}
	
	function imageOff(imageName) {
		fileName = document[imageName].src;
		fileName = fileName.substring(0, fileName.length - 7);
		document[imageName].src = fileName + ".gif";
	}
	
	function chgImg(imageName, chgImagePath) {
		document[imageName].src = chgImagePath;
	}