最简单的方法来检索跨浏览器XmlHttpRequest [英] Easiest way to retrieve cross-browser XmlHttpRequest

问题描述

检索适用于所有浏览器的XmlHttpRequest对象的最简单和最安全的方法是什么？没有任何额外的库。是否有您经常使用的代码段？

What is the easiest and safest way to retrieve XmlHttpRequest object that works across all browsers? Without any extra libraries. Is there a code snippet you use often?

我知道网上有很多例子，但这正是我要求的原因：有太多不同的例子，我只想要一些简单的，被证明是有效的。

P.S. I know there are tons of examples on the net, but this is precisely the reason I am asking: there are too many different examples, and I just want something simple and proven to work.

jQuery和其他库不是选项。

jQuery and other libraries is NOT an option. Why does jquery leak memory so badly?

推荐答案

我有时使用这个片段从< a href =http://www.quirksmode.org/js/xmlhttp.html =nofollow noreferrer> quirksmode.org

I sometimes use this snippet from quirksmode.org

但）

function sendRequest(url,callback,postData) {
    var req = createXMLHTTPObject();
    if (!req) return;
    var method = (postData) ? "POST" : "GET";
    req.open(method,url,true);
    req.setRequestHeader('User-Agent','XMLHTTP/1.0');
    if (postData)
        req.setRequestHeader('Content-type','application/x-www-form-urlencoded');
    req.onreadystatechange = function () {
        if (req.readyState != 4) return;
        if (req.status != 200 && req.status != 304) {
//          alert('HTTP error ' + req.status);
            return;
        }
        callback(req);
    }
    if (req.readyState == 4) return;
    req.send(postData);
}

var XMLHttpFactories = [
    function () {return new XMLHttpRequest()},
    function () {return new ActiveXObject("Msxml2.XMLHTTP")},
    function () {return new ActiveXObject("Msxml3.XMLHTTP")},
    function () {return new ActiveXObject("Microsoft.XMLHTTP")}
];

function createXMLHTTPObject() {
    var xmlhttp = false;
    for (var i=0;i<XMLHttpFactories.length;i++) {
        try {
            xmlhttp = XMLHttpFactories[i]();
        }
        catch (e) {
            continue;
        }
        break;
    }
    return xmlhttp;
}

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