diff --git a/assets/service-worker.js b/assets/service-worker.js
index 4ef5972..3ef31a2 100644
--- a/assets/service-worker.js
+++ b/assets/service-worker.js
@@ -1,4 +1,4 @@
-var cacheName = 'hugo-nuo-v2';
+var cacheName = 'hugo-nuo-v5';
 var filesToCache = [
   '404.html',
   'favicon.ico',
@@ -44,26 +44,45 @@ self.addEventListener('install', event => {
   event.waitUntil(caches.open(cacheName).then(cache => cache.addAll(filesToCache)));
 });
 
-// Serve files from the cache
+// network first
 self.addEventListener('fetch', event => {
   event.respondWith(
-    caches
-      .match(event.request)
-      .then(response => {
-        if (response) return response;
-        return fetch(event.request);
-      })
-      .then(response => {
-        if (response.status === 404) return caches.match('404.html');
-        return caches.open(cacheName).then(cache => {
-          cache.put(event.request.url, response.clone());
+    caches.open(cacheName).then(function(cache) {
+      return fetch(event.request)
+        .then(function(response) {
+          if (response.status === 404) return caches.match('404.html');
+          cache.put(event.request, response.clone());
           return response;
+        })
+        .catch(function() {
+          return caches.match(event.request);
         });
-      })
-      .catch(error => console.log('Error, ', error)),
+    }),
   );
 });
 
+// cache-first
+// If you want to use cache first, you should change cacheName manually
+
+// self.addEventListener('fetch', event => {
+//   event.respondWith(
+//     caches
+//       .match(event.request)
+//       .then(response => {
+//         if (response) return response;
+//         return fetch(event.request);
+//       })
+//       .then(response => {
+//         if (response.status === 404) return caches.match('404.html');
+//         return caches.open(cacheName).then(cache => {
+//           cache.put(event.request.url, response.clone());
+//           return response;
+//         });
+//       })
+//       .catch(error => console.log('Error, ', error)),
+//   );
+// });
+
 // Delete outdated caches
 self.addEventListener('activate', event => {
   const cacheWhitelist = [cacheName];