Listener('load', () => {
        navigator.serviceWorker.register('./sw.js').then(() => {
          cacheOnlyEmpty.addEventListener('click', () => {
            fetch('cache-only-empty-cache.txt').catch(() => {});
          });

          cacheOnlyPopulated.addEventListener('click', () => {
            fetch('cache-only-populated-cache').then((response) => {
              return response.text();
            });
          });

          cacheFirst.addEventListener('click', () => {
            fetch('cache-fi