https://sb-je.si/service-worker.js

1self.addEventListener('install', function(event) {
2	event.waitUntil(			
3		caches.open('offline').then(function(cache) {
4			return cache.add('/offline.html');
5		})
6	);
7});
8
9self.addEventListener('fetch', function(event) {
10	if (event.request.mode === 'navigate' && event.request.method === 'GET') {
11		return event.respondWith(
12			fetch(event.request).catch(function(error) {
13				return caches.open('offline').then(function(cache) {
14					return cache.match('/offline.html');
15				})
16			})
17		);
18	}
19});