function requestText() {
    var left_schedule = document.getElementById("left_schedule");
    var xmlhttp = createXMLHttp();
    if(xmlhttp) {
        try {
            xmlhttp.onreadystatechange = gotData;
            xmlhttp.open("GET", "new_info.txt", true);
            xmlhttp.send(null);
        }
        catch(e) {
            left_schedule.innerHTML = "メンテナンス中";
        }
    }
    else
        left_schedule.innerHTML = "XMLHttpRequest利用不可";
    
    function gotData() {
        if(xmlhttp.readyState != 4) return;
        
        if(xmlhttp.status == 200 || xmlhttp.status == 0)
            left_schedule.innerHTML = xmlhttp.responseText;
        else
            left_schedule.innerHTML = "HTTPエラー：" + xmlhttp.status;
    }
}

function createXMLHttp() {
    var obj = null;
    try {  // Mozilla, Opera, Safari, IE 7
        obj = new XMLHttpRequest();
    }
    catch(e) {
        try { // IE 6
            obj = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch(e) {
            try { // IE 5, 5.5
                obj = new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch(e) { }
        }
    }
    return obj;
}