The periodicsync event of the ServiceWorkerGlobalScope interface is fired at timed intervals, specified when registering a PeriodicSyncManager.

This event is not cancelable and does not bubble.

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("periodicsync", (event) => {});

onperiodicsync = (event) => {};

A PeriodicSyncEvent. Inherits from Event.

Inherits properties from its ancestor, Event.

PeriodicSyncEvent.tag Read only

Returns the developer-defined identifier for this PeriodicSyncEvent. Multiple tags can be used by the web app to run different periodic tasks at different frequencies.

The following example shows how to respond to a periodic sync event in the service worker.

self.addEventListener("periodicsync", (event) => {
  if (event.tag === "get-latest-news") {
    event.waitUntil(fetchAndCacheLatestNews());
  }
});

You can also set up the event handler using the onperiodicsync property:

self.onperiodicsync = (event) => {
  // ...
};

• Richer offline experiences with the Periodic Background Sync API
• A Periodic Background Sync demo app