function chgButtonDown(num) {
		document.getElementById('cell_b' + num).className = 'hg2_b' + num + '_over';
	}
	
	function chgButtonUp(num) {
		document.getElementById('cell_b' + num).className = 'hg2_b' + num;
	}
	
	function menuGo(url) {
		document.location.href = url;
	}