// Register service worker
            if ('serviceWorker' in navigator) {
                document.addEventListener('DOMContentLoaded', () => {
                    setTimeout(initSW, 3500);
                });
                document.addEventListener('scroll', initSWEvent);
                document.addEventListener('mousemove', initSWEvent);
                document.addEventListener('touchstart', initSWEvent);

                function initSW() {
                    if (window.swDidInit) {
                        return false;
                    }
                    window.swDidInit = true; // flag to ensure script does not get added to DOM more than once
                    navigator.serviceWorker
                        .register('/sw.js')
                        .then(() => { console.log('Service Worker Registered'); });
                }

                function initSWEvent() {
                    initSW();
                    event.currentTarget.removeEventListener(event.type, initSWEvent);
                }
            }