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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The ServiceWorkerRegistration interface of the ServiceWorker API represents the service worker registration. You register a service worker to control one or more pages that share the same origin.

The lifetime of a service worker registration is beyond that of the ServiceWorkerRegistration objects that represent them within the lifetime of their corresponding service worker clients. The browser maintains a persistent list of active ServiceWorkerRegistration objects.

Note: This feature is available in Web Workers.


Also implements properties from its parent interface, EventTarget.

ServiceWorkerRegistration.scope Read only
Returns a unique identifier for a service worker registration. This must be on the same origin as the document that registers the ServiceWorker.
ServiceWorkerRegistration.installing Read only
Returns a service worker whose state is installing. This is initially set to null.
ServiceWorkerRegistration.waiting Read only
Returns a service worker whose state is waiting. This is initially set to null. Read only
Returns a service worker whose state is either activating or activated. This is initially set to null. An active worker will control a ServiceWorkerClient if the client's URL falls within the scope of the registration (the scope option set when ServiceWorkerContainer.register is first called.)
ServiceWorkerRegistration.navigationPreload Read only
Returns the instance of NavigationPreloadManager associated with the current service worker registration.
serviceWorkerRegistration.periodicSync Read only
Returns a reference to the PeriodicSyncManager interface, which manages periodic background synchronization processes.
ServiceWorkerRegistration.pushManager Read only
Returns a reference to the PushManager interface for managing push subscriptions including subscribing, getting an active subscription, and accessing push permission status.
ServiceWorkerRegistration.sync  Read only  
Returns a reference to the SyncManager interface, which manages background synchronization processes.

Event handlers

ServiceWorkerRegistration.onupdatefound Read only
An EventListener property called whenever an event of type updatefound is fired; it is fired any time the ServiceWorkerRegistration.installing property acquires a new service worker.


Also implements methods from its parent interface, EventTarget.

Returns a Promise that resolves to an array of Notification objects.
Displays the notification with the requested title.
Checks the server for an updated version of the service worker without consulting caches.
Unregisters the service worker registration and returns a promise (see Promise). The service worker will finish any ongoing operations before it is unregistered.


The code first checks to see if the browser supports service workers. If supported, the code registers the service worker.

If it's a new or updated service worker, it obtains a reference to the service worker inside of the registration's updatefound event, allowing you to listen to further changes in that service worker's state.

If the service worker hasn't changed since the last time it was registered, than the updatefound event will not be fired.

if ('serviceWorker' in navigator) {
  navigator.serviceWorker.register('/sw.js').then(function(registration) {
    registration.onupdatefound = function() {
      // If updatefound is fired, it means that there's
      // a new service worker being installed.
      var installingWorker = registration.installing;
      console.log('A new service worker is being installed:',

      // You can listen for changes to the installing service worker's
      // state via installingWorker.onstatechange
  }).catch(function(error) {
    console.log('Service worker registration failed:', error);
} else {
  console.log('Service workers are not supported.');


Specification Status Comment
Service Workers
The definition of 'ServiceWorkerRegistration' in that specification.
Editor's Draft Initial definition.
Push API
The definition of 'PushManager' in that specification.
Working Draft Adds the pushManager property.
Notifications API Living Standard Adds the showNotification() method and the getNotifications() method.
Web Background Synchronization Living Standard Adds the sync property.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 40 44.0 (44.0)[1] No support ? No support
Available in web workers (Yes) 44.0 (44.0)[1] No support ? No support
getNotifications(), showNotification() (Yes) 46.0 (46.0)[1] No support ? No support
navigationPreload 59 ? ? ? ?
sync property 49 ? ? ? ?
Feature Android Webview Chrome for Android Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile
Basic support No support 40.0 44.0 (44.0) (Yes) No support ? No support
Available in web workers No support (Yes) 44.0 (44.0) (Yes) No support ? No support
getNotifications(), showNotification() No support (Yes) 46.0 (46.0) (Yes) No support ? No support
navigationPreload No support 59 ? ? ? ? ?
sync property No support 49 ? ? ? ? ?

[1] Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR.)

See also

Document Tags and Contributors

 Last updated by: jeffposnick,