Why does this cross-domain request work in other browsers but not IE9?

Question

I have some Ajax code that is working in Safari, Chrome and Firefox but not in IE9.

The page is on http://foo.com/test.aspx and it\'s making an AJAX r

Answer 1

Instead of $.ajax(), use this custom code:

function newpostReq(url,callBack)
{
    var xmlhttp;
    if (window.XDomainRequest)
    {
        xmlhttp=new XDomainRequest();
        xmlhttp.onload = function(){callBack(xmlhttp.responseText)};
    }
    else if (window.XMLHttpRequest)
        xmlhttp=new XMLHttpRequest();
    else
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    xmlhttp.onreadystatechange=function()
    {
        if (xmlhttp.readyState==4 && xmlhttp.status==200)
            callBack(xmlhttp.responseText);
    }
    xmlhttp.open("GET",url,true);
    xmlhttp.send();
}

Note: this works for GET requests.

To adapt it on POST requests change the following lines:

function newpostReq(url,callBack,data)

data is the URL encoded parameters of the post requests such as : key1=value1&key2=value%20two

    xmlhttp.open("POST",url,true);
    try{xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");}catch(e){}
    xmlhttp.send(data);

To summarize, open the connection as POST request (Line 1), set the request header for urlencoded type of the post data (wrap it with try-catch for exceptional browsers) (Line 2), then send the data (Line 3).