text: self.addEventListener('install', function(event) {
      event.waitUntil(
          caches.open('SDLchip').then(function(cache) {
              return cache.addAll([
                  'index.html',
                  'SDLchip.js',
                  'SDLchip.wasm'
              ]);
          })
      );
  });
  self.addEventListener('fetch', function(event) {
      event.respondWith(
          caches.match(event.request).then(function(response) {
              return response || fetch(event.request);
          })
      );
  });
  