Exposes the client's PageLifecycle state on the ServiceWorker Client API.


Service workers do not know the state of a client. If a client is frozen it will not immediately handle a postMessage() being sent to it. In some situations the service worker may not wish to spam the client with messages because that may cause the client to be discarded. In other situations the service worker may wish to focus the window client causing the client to become unfrozen.



Specification link

Specification being incubated in a Community Group

Status in Chromium


In developer trial (Behind a flag) (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.


Search tags

frozen, service worker,

Last updated on 2021-12-13