AJAX的请求实例

来源：互联网发布：淘宝待发货多久编辑：程序博客网时间：2024/06/05 09:46

发送一个简单的HTTP请求. 我们用JavaScript请求一个HTML文件： test.html, 文件的文本内容为 "I'm a test." 然后我们"alert()"弹出test.html文件的内容.

<html><script type="text/javascript" language="javascript">    var http_request = false;    function makeRequest(url) {        http_request = false;        if (window.XMLHttpRequest) { // Mozilla, Safari,...            http_request = new XMLHttpRequest();            if (http_request.overrideMimeType) {//服务器的响应没有XML mime-type header                http_request.overrideMimeType('text/xml');            }        } else if (window.ActiveXObject) { // IE            try {                http_request = new ActiveXObject("Msxml2.XMLHTTP");            } catch (e) {                try {                    http_request = new ActiveXObject("Microsoft.XMLHTTP");                } catch (e) {}            }        }        if (!http_request) {            alert('Giving up :( Cannot create an XMLHTTP instance');            return false;        }        http_request.onreadystatechange = alertContents;        http_request.open('GET', url, true);        http_request.send(null);    }    function alertContents() {        if (http_request.readyState == 4) {// 4:装载完毕            if (http_request.status == 200) {                alert(http_request.responseText);//以文本字符串的方式返回服务器的响应            } else {                alert('There was a problem with the request.');            }        }    }</script><span    style="cursor: pointer; text-decoration: underline"         <!--cursor:鼠标显示类型  -->    onclick="makeRequest('test.html')"><!--调用makeRequest()方法-->        Make a request</span></html>