calendar-update.js

var CLIENT_ID = web.client_id;

var SCOPES = ["https://www.googleapis.com/auth/calendar"];

function checkAuth() {
  gapi.auth.authorize(
    {
      'client_id': CLIENT_ID,
      'scope': SCOPES.join(' '),
      'immediate': true
    }, handleAuthResult);
}

function handleAuthResult(authResult) {
  var authorizeDiv = document.getElementById('authorize-div');
  if (authResult && !authResult.error) {

    authorizeDiv.style.display = 'none';
    loadCalendarApi();
  } else {

    authorizeDiv.style.display = 'inline';
  }
}

function handleAuthClick(event) {
  gapi.auth.authorize(
    {client_id: CLIENT_ID, scope: SCOPES, immediate: false},
    handleAuthResult);
  return false;
}

function loadCalendarApi() {
  gapi.client.load('calendar', 'v3', listUpcomingEvents);
}

function listUpcomingEvents() {
  var event = {
    'summary': 'ocupado',
    'start': {
      'dateTime': '2016-04-16T09:00:00-07:00',
      'timeZone': 'America/Los_Angeles'
    },
    'end': {
      'dateTime': '2016-04-16T17:00:00-07:00',
      'timeZone': 'America/Los_Angeles'
    }
  };

  var request = gapi.client.calendar.events.update({
    'calendarId': 'primary',
    'eventId' : '91omdjkqse514b05uubben1npc',
    'resource': event
  });

  request.execute(function(event) {
    appendPre('Event created: ' + event.htmlLink);
  });
}

function appendPre(message) {
  var pre = document.getElementById('output');
  var textContent = document.createTextNode(message + '\n');
  pre.appendChild(textContent);
}