function listFold(year) {
	var element = document.getElementById("month_" + year);
	if (element.style.display != "none") {
		element.style.display = "none";
	}else {
		element.style.display = "block";
	}
}

window.onload = function() {
	var none_flg = false;

	var elements = document.getElementsByTagName("ul");
	
	for (var i = 0; i < elements.length; i++) {
		if(elements[i].className == "month") {
			if (none_flg) {
				elements[i].style.display = "none";
			} else {
				none_flg = true;
			}
		}
	}
}