>[...] could do their work even after the page is closed, provided the user has given permission.<p>I'm really glad for the second half of that statement.<p>While I could imagine a few use cases, the last thing I want on my smartphone are arbitrary bloated sites draining my battery after closing them. I even consider it a feature of websites vs. native apps.
Service Workers are what Application Cache should have been first. Application Cache has a big flaw and that is, you can't control it much. You depend on browser to decide what to do when there is no Internet connection. With Service Workers you get to programmatically tell browser what to do with network requests and so on.<p>Classic configuration file vs. let me write actual code approach. I'm glad we have both now! Application Cache makes sense for a lot of static websites.
I'm glad it's a native feature.<p>I attended a talk by an FT engineer and I was amazed by what's possible.<p>Update: Mistakenly thought that FT uses Polyfill for service workers.