code: function init() {
          // initialize the SDK with the domain where Just is running and the
          // OAuth 2.0 implicit flow parameters
          sdk = new window.JustSDK({
              domain: 'JUSTDOMAIN',
              oauth2: {
                  // adapt this to point to the correct domain and path
                  redirect_uri: 'https://YOURDOMAIN/browser-app-authorized.html',
                  // the client ID of this app. Must have been registered at the
                  // Just installation configured under 'domain' above.
                  client_id: 'YOUR_CLIENT_ID',
                  flow: 'implicit'
              }
          });
  
          var loginBtn = document.querySelector('#login');
          var logoutBtn = document.querySelector('#logout');
  
          loginBtn.addEventListener('click', function() {
              printInfo();
          });
          logoutBtn.addEventListener('click', function() {
              window.localStorage.removeItem('just:accessToken:' + sdk.config.domain);
              window.location.reload();
          });
          getToken(false).then(function() {
              logoutBtn.style.display = '';
              loginBtn.style.display = 'none';
              printInfo();
          }, function() {
              loginBtn.style.display = '';
              logoutBtn.style.display = 'none';
          });
      }
docs: this function is called right after the DOM has loaded