XMLHttpRequest reference implementation

gistfile1.txt

var req;

function loadXML(url) {
    req = false;
    // native JavaScript XMLHttpRequest Objekt 
    if (window.XMLHttpRequest && !(window.ActiveXObject)) {
        try {
            req = new XMLHttpRequest();
        } catch (e) {
            req = false;
        }
    // IE ActiveX XMLHttpRequest Objekt
    } else if (window.ActiveXObject) {
        try {
            req = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
                req = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {
                req = false;
            }
        }
    }
    if (req) {
        req.onreadystatechange = processReqest;
        req.open("GET", url, true);
        req.send("");
    }
}