[jQuery] ajax error handling troubles

[jQuery] ajax error handling troubles


        $.ajax({
            async: true,
            url: testingURL,
            success: function () {
                location.reload();
            },
            error: function (XMLHttpRequest, textStatus, errorThrown) {
                console.log('error throw');
                console.log(errorThrown);
            }
        });
the requested page can return 404 or 403 error codes
but the errorThrown variable is ALWAYS undef...
any idea ??