/* Load Area or Station Selectbox */
function loadOptions(erea_key, url) {
	try {
		var target_id = document.getElementById(erea_key).options[document.getElementById(erea_key).selectedIndex].value;
		var change_event = "";
		if (erea_key=="large_area") {
				document.getElementById("middle_areaparent").innerHTML = "<select><option>▼エリアを選んでください</option></select>";
				document.getElementById("middle_areaparent").style.visibility = "visible";
		}
		var http_obj = createXMLHttp();
		if (http_obj) {
			http_obj.onreadystatechange = function() {
				if (http_obj.readyState == 4 && http_obj.status == 200) {
					ret = http_obj.responseText;
					if (erea_key=="large_area") {
						if (ret != "" && ret != "ERROR!!") {
							document.getElementById("middle_areaparent").innerHTML = "<select id=\"middle_area\" name=\"middle_area\">" + "<option value=\"\">▼エリアを選んでください</option>" + ret + "</select>";
							document.getElementById("middle_areaparent").style.visibility = "visible";
						} else {
							document.getElementById("middle_areaparent").innerHTML = "<select><option>▼エリアを選んでください</option></select>";
							document.getElementById("middle_areaparent").style.visibility = "visible";
						}
					}
				}
			}
			if (erea_key=="large_area") {
				http_obj.open("get", url + "?large_area=" + target_id, true);
			}
			http_obj.send(null);
		}
	} catch(e) { null; }
	return true;
	alert(change_event);
}

/* Create Xml Http Connection */
function createXMLHttp() {
	try {
		return new XMLHttpRequest();
	} catch (e) {
		try {
			return new ActiveXObject("Microsoft.XMLHTTP");
		} catch (e) {
			return null;
		}
	}
	return null;
}