Weird issue with jQuery .ajax POST and webkit browsers (contao related)

Today I stumbled over some weird issue with jQuery and webkit browsers when sending a POST request. While in Firefox I get the response (with a status code 200) in webkit browsers (chrome, midori, safari) a 204 (no content) status code is returned. Switching to GET solves this.

I’ve used the following code:

$('#button').on('click', function () {
    $.ajax({
        type: "POST",
        dataType: 'text',
        url: "/" + language + "/test.html",
        data: { 'shopAdd': "true", 'product': "5" }
    })
    .done(function (msg) {
        alert("Data Saved: " + msg);
    })
    .fail(function () {
        alert("error");
    });
    
    return false;
});

In the called page is a snippet which does:

$_SESSION['Shop'][] = $_POST['product'];
echo time();
die();

So there is no output apart from a timestamp. I am using Contao here, so the 204 might be returned by Contao instead of by the Server but then: In firefox the correct response is returned. Modifying the above to use GET instead of POST makes it work in firefox as well as webkit browsers.

I don’t even have any idea how to debug that.

In a free moment Sven (thanks) took a look and found the following snippet within Contao:

if ($_POST && !RequestToken::validate(Input::post('REQUEST_TOKEN')))
{
    // Force a JavaScript redirect upon Ajax requests (IE requires absolute link)
    if (Environment::get('isAjaxRequest'))
    {
        header('HTTP/1.1 204 No Content');
        header('X-Ajax-Location: ' . Environment::get('base') . 'contao/');
    }

So basically: Contao sends a 204 no content, if it is an ajax (POST) request and if the Request token has not been submitted. Still I have no idea WHY this does work without a request token in firefox.

It does work in Firefox as long as you’re logged in to the backend. If you logout it won’t work in Firefox neither. Who wants a COOKIE!