# Monitoring the user's session state

> [!WARNING]
> **Warning:** The Google Sign-In library optionally uses FedCM APIs, and their use will become a requirement. [Conduct an impact assessment](https://developers.google.com/identity/sign-in/web/gsi-with-fedcm) to confirm that user sign-in continues to function as expected.   
>
> Support for the Google Sign-In library is deprecated, see the [Deprecation and Sunset](https://developers.google.com/identity/sign-in/web/deprecation-and-sunset) guide for more.

After the Google Sign-In client has been initialized, you can attach
handlers that check various attributes and methods of the client to determine
the user's session state. You can use information returned by the client object
to help sync your site's user experience across multiple tabs and devices for
your user.

The following code demonstrates using the 2.0 client method
`attachClickHandler` to create a callback that either silently finishes sign-in
for the user, or prompts the user to re-authorize based on the state of the
user's session.

    /**
     * The Sign-In client object.
     */
    var auth2;

    /**
     * Initializes the Sign-In client.
     */
    var initClient = function() {
        gapi.load('auth2', function(){
            /**
             * Retrieve the singleton for the GoogleAuth library and set up the
             * client.
             */
            auth2 = gapi.auth2.init({
                client_id: 'CLIENT_ID.apps.googleusercontent.com'
            });

            // Attach the click handler to the sign-in button
            auth2.attachClickHandler('signin-button', {}, onSuccess, onFailure);
        });
    };

    /**
     * Handle successful sign-ins.
     */
    var onSuccess = function(user) {
        console.log('Signed in as ' + user.getBasicProfile().getName());
     };

    /**
     * Handle sign-in failures.
     */
    var onFailure = function(error) {
        console.log(error);
    };