问题
Actually, I want to do background periodic sync in my pwa but,I have searched this at google but don't find the relevant answer that I want!
回答1:
Periodic background sync does not currently exist outside of this proposal document. It's not currently part of any web standard, and no browsers have added support for it inside of their service worker implementation.
While there is support for background sync inside of a service worker, it's a one-off, not repeated at a time interval.
来源：https://stackoverflow.com/questions/51773937/how-to-do-periodic-background-sync-in-progressive-web-apps