Question

I try to make Cross Domain POST requests and get back JSON encoded responses,

everything works fine except in IE 7, 8, 9.
I have try those solutions but i get this error:

Object doesn’t support property or method ‘setRequestHeader’

Function createXMLHTTPObject() – attempt 1

function createXMLHTTPObject() {
    var xmlhttp = false;
        var is_IE = window.XDomainRequest ? true : false;
        if (is_IE) {
            xmlhttp = new window.XDomainRequest();
        } else {
            if (window.XMLHttpRequest) {
                xmlhttp = new XMLHttpRequest();
            } else {
                xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
            }
        }
    return xmlhttp;
}

Function createXMLHTTPObject() – attempt 2

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; 
}

Function send()
Here it returns the error, at: req.setRequestHeader('User-Agent', 'XMLHTTP/1.0');

function send(postData, callback) {
    var url = 'http://domain.com/ajax-processing.php'; //url overlap
    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) {
            console.log('HTTP error ' + req.status);
            return;
        }
        callback(req);
    }
    if (req.readyState == 4) return;
    req.send(postData); 
}

Here i call the send function

var insert = 'id=1&type=insert';
CLib.send(insert, function(data) {
    console.log(data);
});

Is it possible to make Cross Domain requests in IE?
How i can leave behind this part, without using any other library like jQuery?

Answer 1

Thanks a lot @Esailija who inform me that i can’t make set request headers with the XDomainRequest.

So i tried other methods and solutions also and i finally came back with a simpler method:
changed the POST requests to GET and everything working fine after some small changes.