ajax站內簡訊擷取代碼

var timeout = null; //setInterval函數控制代碼
var xmlHttp = false; //
//初始化XMLHttpRequest對象
function createXmlHttp(){
    xmlHttp = false;
    if (window.ActiveXObject) {
        try {xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");}
        catch (e) {xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");}
    }else if (window.XMLHttpRequest) {xmlHttp = new XMLHttpRequest();}
}
//非同步呼叫頁面擷取結果timestamp為了不讓瀏覽器緩衝結果
function sendRequest(){
    createXmlHttp();
    var url = "/message/getmessage.asp教程?timestamp=" + new Date().getTime();
    if (!xmlHttp) {
        alert("XMLHttpRequest is not Create!");
    }
    xmlHttp.open("GET", url, true);
    xmlHttp.onreadystatechange = function(){//回呼函數開始
        var tag = document.getElementById("newmsg");
        tag.innerHTML = "";
        if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
            if (xmlHttp.responseText>0) {
               tag.innerHTML= "<img src='/images/msg.gif' width='16' height='15' /> 您有[ "+xmlHttp.responseText+" ]封未讀郵件";
            }else{
               tag.innerHTML="";   
            }
        }
    }//回呼函數結束
xmlHttp.send(null);
}

//開始自動重新整理
function update(){
timeout = window.setInterval("sendRequest()", 10000);//設定10秒調用一次update頁面
}
//停止自動重新整理
function Stopupdate(){
if (timeout != null) {
window.clearInterval(timeout);
}
}%>