CAKE_PHP_TERRITORY/app/webroot/js/app.js

document.addEventListener('DOMContentLoaded', function () {
    var switcher = document.querySelector('.site-app-switcher');
    if (!switcher) {
        return;
    }

    var toggle = switcher.querySelector('.site-app-switcher-toggle');

    toggle.addEventListener('click', function (event) {
        event.stopPropagation();
        var isOpen = switcher.classList.toggle('is-open');
        toggle.setAttribute('aria-expanded', isOpen ? 'true' : 'false');
    });

    document.addEventListener('click', function (event) {
        if (!switcher.contains(event.target)) {
            switcher.classList.remove('is-open');
            toggle.setAttribute('aria-expanded', 'false');
        }
    });

    document.addEventListener('keydown', function (event) {
        if (event.key === 'Escape') {
            switcher.classList.remove('is-open');
            toggle.setAttribute('aria-expanded', 'false');
        }
    });
});