创建ajax异步对象,ajax 异步获取数据实现代码 （js创建ajax对象）

var request = false;

try {

request = new XMLHttpRequest();

} catch (trymicrosoft) {

try {

request = new ActiveXObject("Msxml2.XMLHTTP");

} catch (othermicrosoft) {

try {

request = new ActiveXObject("Microsoft.XMLHTTP");

} catch (failed) {

request = false;

}

}

}

if (!request) alert("Error initializing XMLHttpRequest!");

//获取信息

function GetInfo() {

var url = "test.aspx?userName=" + document.getElementById("txtName").value;

request.open("GET", url, true);

request.onreadystatechange = updatePageTime;

request.send(null);

}

//更新页面

function updatePageTime() {

if (request.readyState == 4) {

if (request.status == 200) {

var response = request.responseText;

document.getElementById("txtLoginName").value = response;

} else if (request.status == 404) {

alert("Requested URL is not found.");

} else if (request.status == 403) {

alert("Access denied.");

} else

alert("status is " + request.status);

}

}

// -->