beforeSend: function(xhr) {
                    try {
                        xhr.withCredentials = true;
                    } catch (e) {
                        var nativeOpen = xhr.open;
                        xhr.open = function() {
                            var result = nativeOpen.apply(xhr, arguments);
                            xhr.withCredentials = true;
                            return result;
                        };
                    }
                }