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The ServiceWorkerGlobalScope interface of the ServiceWorker API represents the global execution context of a service worker.

Developers should keep in mind that the ServiceWorker state is not persisted across the termination/restart cycle, so each event handler should assume it's being invoked with a bare, default global state.

Once successfully registered, a service worker can and will be terminated when idle to conserve memory and processor power. An active service worker is automatically restarted to respond to events, such as ServiceWorkerGlobalScope.onfetch or ServiceWorkerGlobalScope.onmessage.

Additionally, synchronous requests are not allowed from within a service worker — only asynchronous requests, like those initiated via the fetch() method, can be used.

This interface inherits from the WorkerGlobalScope interface, and its parent EventTarget, and therefore implements properties from WindowTimers, WindowBase64, and WindowEventHandlers.

Properties

ServiceWorkerGlobalScope.clients Read only
Contains the Clients object associated with the service worker.
ServiceWorkerGlobalScope.registration Read only
Contains the ServiceWorkerRegistration object that represents the service worker's registration.
ServiceWorkerGlobalScope.caches Read only
Contains the CacheStorage object associated with the service worker.

Events

activate
Occurs when a ServiceWorkerRegistration acquires a new ServiceWorkerRegistration.active worker.
Also available via the ServiceWorkerGlobalScope.onactivate property.
fetch
Occurs when a fetch() is called.
Also available via the ServiceWorkerGlobalScope.onfetch property.
install
Occurs when a ServiceWorkerRegistration acquires a new ServiceWorkerRegistration.installing worker.
Also available via the ServiceWorkerGlobalScope.oninstall property.
message
Occurs when incoming messages are received. Controlled pages can use the MessagePort.postMessage() method to send messages to service workers. The service worker can optionally send a response back via the MessagePort exposed in event.data.port, corresponding to the controlled page.
Also available via the ServiceWorkerGlobalScope.onmessage property.
notificationclick
Occurs when a user clicks on a displayed notification.
Also available via the ServiceWorkerGlobalScope.onnotificationclick property.
notificationclose
Occurs — when a user closes a displayed notification.
Also available via the ServiceWorkerGlobalScope.onnotificationclose property.
push
Occurs when a server push notification is received.
Also available via the ServiceWorkerGlobalScope.onpush property.
pushsubscriptionchange
Occurs when a push subscription has been invalidated, or is about to be invalidated (e.g. when a push service sets an expiration time).
Also available via the ServiceWorkerGlobalScope.onpushsubscriptionchange property.
sync
Triggered when a call to SyncManager.register is made from a service worker client page. The attempt to sync is made either immediately if the network is available or as soon as the network becomes available. 
Also available via the ServiceWorkerGlobalScope.onsync property.

Methods

ServiceWorkerGlobalScope.skipWaiting()
Allows the current service worker registration to progress from waiting to active state while service worker clients are using it.

ServiceWorkerGlobalScope implements WorkerGlobalScope — which implements WindowOrWorkerGlobalScope. Therefore it also has the following property available to it:

GlobalFetch.fetch()
Starts the process of fetching a resource. This returns a promise that resolves to the Response object representing the response to your request. This algorithm is the entry point for the fetch handling handed to the service worker context.

Examples

This code snippet is from the service worker prefetch sample (see prefetch example live.) The ServiceWorkerGlobalScope.onfetch event handler listens for the fetch event. When fired, the code returns a promise that resolves to the first matching request in the Cache object. If no match is found, the code fetches a response from the network.

The code also handles exceptions thrown from the fetch() operation. Note that an HTTP error response (e.g., 404) will not trigger an exception. It will return a normal response object that has the appropriate error code set.

self.addEventListener('fetch', function(event) {
  console.log('Handling fetch event for', event.request.url);

  event.respondWith(
    caches.match(event.request).then(function(response) {
      if (response) {
        console.log('Found response in cache:', response);

        return response;
      }
      console.log('No response found in cache. About to fetch from network...');

      return fetch(event.request).then(function(response) {
        console.log('Response from network is:', response);

        return response;
      }, function(error) {
        console.error('Fetching failed:', error);

        throw error;
      });
    })
  );
});

Specifications

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

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
ServiceWorkerGlobalScopeChrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
activate event
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
clients
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
caches
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
install event
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
message event
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
notificationclick eventChrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android No support NoChrome Android Full support 40Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
onabortpayment
Experimental
Chrome Full support 61
Disabled
Full support 61
Disabled
Disabled From version 61: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled). To change preferences in Chrome, visit chrome://flags.
Edge ? Firefox ? IE No support NoOpera ? Safari Full support 11.1WebView Android No support NoChrome Android Full support 61
Disabled
Full support 61
Disabled
Disabled From version 61: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android ? Opera Android ? Safari iOS Full support 11.1Samsung Internet Android ?
onactivate
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
oncanmakepayment
Experimental
Chrome Full support 61
Disabled
Full support 61
Disabled
Disabled From version 61: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled). To change preferences in Chrome, visit chrome://flags.
Edge ? Firefox ? IE No support NoOpera ? Safari ? WebView Android No support NoChrome Android Full support 61
Disabled
Full support 61
Disabled
Disabled From version 61: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android ?
onfetch
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
oninstall
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
onmessage
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
onmessageerrorChrome ? Edge ? Firefox ? IE No support NoOpera ? Safari ? WebView Android ? Chrome Android ? Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android ?
onnotificationclick
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
onnotificationclose
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
onpaymentrequest
Experimental
Chrome Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled). To change preferences in Chrome, visit chrome://flags.
Edge ? Firefox ? IE No support NoOpera ? Safari ? WebView Android No support NoChrome Android Full support 57
Disabled
Full support 57
Disabled
Disabled From version 57: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled). To change preferences in Chrome, visit chrome://flags.
Firefox Android ? Opera Android ? Safari iOS ? Samsung Internet Android ?
onpush
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
onpushsubscriptionchange
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
onsync
Experimental
Chrome Full support 49Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 49Chrome Android Full support 49Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 5.0
push eventChrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
pushsubscriptionchange eventChrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
registration
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS Full support 11.1Samsung Internet Android Full support 4.0
skipWaiting
Experimental
Chrome Full support 40Edge ? Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR).
IE No support NoOpera Full support 24Safari No support NoWebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 24Safari iOS No support NoSamsung Internet Android Full support 4.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
See implementation notes.
See implementation notes.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also