ajax 不错的应用

    var http_request = false;

    function makeRequest(url) {

        http_request = false;

        if (window.XMLHttpRequest) { // Mozilla, Safari,…
            http_request = new XMLHttpRequest();
            if (http_request.overrideMimeType) {
                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) {
            if (http_request.status == 200) {
                alert(http_request.responseText);
            } else {
                alert(‘There was a problem with the request.’);
            }
        }

    }

<span
    style=”cursor: pointer; text-decoration: underline”
    onclick=”makeRequest(‘test.html’)”>
        Make a request

</P><P> </P><P> var http_request = false;</P><P> function makeRequest(url) {</P><P> http_request = false;</P><P> if (window.XMLHttpRequest) { // Mozilla, Safari,… http_request = new XMLHttpRequest(); if (http_request.overrideMimeType) { 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) {} } }</P><P> 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);</P><P> }</P><P> function alertContents() {</P><P> if (http_request.readyState == 4) { if (http_request.status == 200) { var xmldoc = http_request.responseXML; var root_node = xmldoc.getElementsByTagName(‘root’).item(0); alert(root_node.firstChild.data); } else { alert(‘There was a problem with the request.’); } }</P><P> } <span style="cursor: pointer;text-decoration: underline"> Make a request </span> </P><P>
[Ctrl+A 全选 注:引入外部Js需再刷新一下页面才能执行]