Signing out using Google API not working

I followed the instructions in:

https://developers.google.com/identity/sign-in/web/sign-in

Everything works (signing in a user) but I cannot sign out a user. I get the following error :

Uncaught gapi.auth2.ExternallyVisibleError: gapi.auth2 has been initialized with different options

It fails when executing :

auth2 = gapi.auth2.init();

(https://developers.google.com/identity/sign-in/web/sign-in#sign_out_a_user)

I need code examples to sign out the user from my web application and also to sign the user completely from the Google account.

gapi.auth2.init(); was called before by

<div class="g-signin2">

which uses gapi.auth2. You should call

auth2 = gapi.auth2.getAuthInstance();

instead of gapi.auth2.init(). Full example:

<a href="#" onclick="signOut();">Sign out</a>
<script>
  function signOut() {
    var auth2 = gapi.auth2.getAuthInstance();
    auth2.signOut().then(function () {
      console.log('User signed out.');
    });
  }
</script>