Inpage Subscribe & Unsubscribe Button

(function () {
    // Cache checkbox reference for enable / disable checkbox
    var getback_push_toggle = document.getElementById('push_toggle');

    // Callback function, will be called by gb_enable_push/gb_disable_push after toggling --> Can be used to give a feedback after a user has enabled or disabled push
    function push_callback(is_push_subscriber) {
        if (is_push_subscriber) {
            console.log('Vielen Dank!');
        } else {
            console.log('Sie wurden von Pushbenachrichtigungen abgemeldet.');
        }
    }

    // Handle push
    function push_handler() {
        if (!window.gb_has_push_support) {
            // No push support detected. Leave checkbox disabled, maybe display an info message etc.
            return;
        }
        // Push support detected. Enable checkbox.
        getback_push_toggle.disabled = false;

        // Set initial state of checkbox
        getback_push_toggle.checked = window.gb_is_push_subscriber;

        // Listen to checkbox changes and fire respective function.
        getback_push_toggle.addEventListener('change', function () {
            if (this.checked) {
                window.gb_enable_push(true, push_callback);
            } else {
                window.gb_disable_push(push_callback);
            }
        });
    }

    // Disable checkbox until Getback is fully loaded and we can request the current status
    getback_push_toggle.disabled = true;

    if (window.getback_loaded) {
        // Getback has already loaded. We can use gb_has_push_support, gb_enable_push() and gb_disable_push().
        push_handler();
    } else {
        // Getback is not yet available. 'getback_loaded' in window gets fired as soon as Getback is loaded
        window.addEventListener('getback_loaded', push_handler);
    }
})();