diff --git a/_includes/nav.html b/_includes/nav.html
index a7bc3d6..23b872a 100644
--- a/_includes/nav.html
+++ b/_includes/nav.html
@@ -1,4 +1,11 @@
 <!-- masthead -->
+<script>
+  if ('serviceWorker' in navigator) {
+    navigator.serviceWorker.register('/sw.js').catch(function (error) {
+        console.error(error);
+    });
+  }
+</script>
 <header class="masthead">
   <div class="container">
     <div class="spacing"></div>
diff --git a/sw.js b/sw.js
new file mode 100644
index 0000000..3e8a103
--- /dev/null
+++ b/sw.js
@@ -0,0 +1,78 @@
+var CACHE_VERSION = 'v1';
+
+self.addEventListener('install', function (event) {
+    event.waitUntil(
+        caches.open(CACHE_VERSION).then(function (cache) {
+            return cache.addAll([
+                '/',
+                '/index',
+                '/it_fair/',
+                '/map/',
+                '/gallery/',
+                '/cosplay/',
+                '/contact/',
+                '/compete/',
+                '/about/',
+                '//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/css/bootstrap.min.css',
+                '//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.4.0/css/font-awesome.min.css',
+                '/assets/css/style.css',
+                '/assets/css/prettyPhoto.css',
+                '/assets/css/hoverex-all.css',
+                '/assets/img/organization/fortinet.png',
+                '/assets/js/jquery.prettyPhoto.js',
+                '/assets/js/custom.js',
+                '//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.4/jquery.min.js',
+                '//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js',
+                '//cdnjs.cloudflare.com/ajax/libs/retina.js/1.3.0/retina.min.js',
+                '//cdnjs.cloudflare.com/ajax/libs/jquery-cookie/1.4.1/jquery.cookie.min.js',
+                '/assets/js/jquery.hoverdir.js',
+                '/assets/js/jquery.hoverex.min.js',
+                '//cdnjs.cloudflare.com/ajax/libs/jquery.isotope/2.2.2/isotope.pkgd.min.js',
+                '/assets/img/organization/cybersec.png',
+                '/assets/img/organization/kperak.png',
+                '/assets/img/organization/cyberhax.png',
+                '/assets/img/organization/syntech.png',
+                '/assets/img/utphax.png',
+                '/assets/img/organization/utp.png',
+                '//cdnjs.cloudflare.com/ajax/libs/font-awesome/4.4.0/fonts/fontawesome-webfont.woff2?v=4.4.0',
+                '//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/fonts/glyphicons-halflings-regular.woff2',
+                '/assets/img/slider-banner.jpg',
+                '/assets/img/slider-cos.jpg',
+                '/assets/img/slider-merch.jpg',
+                '/assets/img/slider-sponsor.jpg',
+                '/assets/img/slider-utphax15.jpg',
+                '/assets/img/slider-baju.jpg',
+                '/assets/img/t-back.jpg',
+                '/assets/img/cosplay.jpg',
+                '/assets/img/Yone_Saizho.jpg',
+                '/assets/img/Ayu_Afrina.jpg',
+                '/assets/img/Yukise_Michi.jpg',
+                '/assets/img/it-fair.jpg'
+            ]).catch(function (error) {
+                console.error('Error in install handler:', error);
+            });
+        })
+    );
+});
+
+self.addEventListener('activate', function (event) {
+    event.waitUntil(
+        caches.keys().then(function (cacheNames) {
+            return Promise.all(
+                cacheNames.map(function (cacheName) {
+                    if (cacheName !== CACHE_VERSION) {
+                        return caches.delete(cacheName);
+                    }
+                })
+            );
+        })
+    );
+});
+
+self.addEventListener('fetch', function (event) {
+    event.respondWith(
+        caches.match(event.request).then(function (response) {
+            return response || fetch(event.request);
+        })
+    );
+});
\ No newline at end of file