A Service Worker can do just that. It is a script which sits between the web page and the server and can intercept requests from the page and responses from the

A Service Worker can do just that. It is a script which sits between the web page and the server and can intercept requests from the page and responses from the server. It can cache responses and serve from cache if it wishes to. So a refresh can result in merely accessing cache. It also supports messaging to and from the page. Having been put in place it's script is fetched once a day to look for changes. It is a very powerful concept and widely supported I believe.