text: importScripts('./cache-polyfill.js');
  self.addEventListener('install', function(e) {
  e.waitUntil(
  caches.open('airhorner').then(function(cache) {
  return cache.addAll([
  './',
  './index.html',
  './index.html?homescreen=1',
  './?homescreen=1',
  './styles/main.css',
  './scripts/main.min.js',
  './sounds/airhorn.mp3'
  ]);
  })
  );
  });
  
  self.addEventListener('fetch', function(event) {
  console.log(event.request.url);
  event.respondWith(
  caches.match(event.request).then(function(response) {
  return response || fetch(event.request);
  })
  );
  });