ServiceWorkerGlobalScope.onactivate

The onactivate property of the ServiceWorkerGlobalScope interface is an event handler fired whenever an activate event occurs (when the service worker activates). This happens after installation, when the page to be controlled by the service worker refreshes.

Syntax

ServiceWorkerGlobalScope.onactivate = function(event) { ... };
ServiceWorkerGlobalScope.addEventListener('activate', function(event) { ... });

Example

The following snippet comes from Using Service Workers; go there for more details.

then.addEventListener('activate', function(event) {
  var cacheWhitelist = ['v2'];

  event.waitUntil(
    caches.forEach(function(cache, cacheName) {
      if (cacheWhitelist.indexOf(cacheName) == -1) {
        return caches.delete(cacheName);
      }
    })
  );
});

Specifications

Specification	Status	Comment
Service Workers The definition of 'Event Handlers' in that specification.	Working Draft	Initial definition

Browser compatibility

[1] Service workers (and Push) have been disabled in the Firefox 45 Extended Support Release (ESR.)

See also

• Using Service Workers
• Service workers basic code example
• Is ServiceWorker ready?
• Promise
• Using web workers