 '?' + qs);
            if (accessToken) {
                xhr.setRequestHeader('Authorization', 'Bearer ' + accessToken);
            }
            xhr.send();
        } else if (params.method.toUpperCase() == 'POST') {
            xhr.open('POST', params.url);
            xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
            if (accessToken) {
                xhr.setRequestHeader('Authorization', 'Bearer ' + accessToken);
            }
            xhr.send(qs);
        }
 