HTML Application Cache
Allow your web apps to work offline
PWA
I'm a strong believer in Progressive Web Apps and using web technologies to build apps for all devices (desktop, tablet, mobile and whatever next). The web needed a bit of time to catch up with native installs but it's almost there.
Service Workers play a big part in bridging the gap. They allow for apps to work offline and receive push notifications. Android now offers the ability to "install" web apps and gives them a more app like feel.
