google firebase facebook include

<!-- Facebook -->
  <!-- [START facebookconfig] -->
  <script src="//connect.facebook.net/en_US/sdk.js"></script>
  <script>
    FB.init({
      /**********************************************************************
       * TODO(Developer): Change the value below with your Facebook app ID. *
       **********************************************************************/
      appId      : '<YOUR_FACEBOOK_APP_ID>',
      status     : true,
      xfbml      : true,
      version    : 'v2.6'
    });
    // [START_EXCLUDE silent]
    // Observe the change in Facebook login status
    // [START facebookauthlistener]
    FB.Event.subscribe('auth.authResponseChange', checkLoginState);
    // [END facebookauthlistener]
    // [END_EXCLUDE]
  </script>
  <!-- [END facebookconfig] -->