Web/API/ServiceWorkerGlobalScope

The ServiceWorkerGlobalScope interface of the Service Worker 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.

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Properties

ServiceWorkerGlobalScope.caches Read only

Contains the CacheStorage object associated with the service worker.

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.

Events

activate

Occurs when a ServiceWorkerRegistration acquires a new ServiceWorkerRegistration.active worker. Also available via the ServiceWorkerGlobalScope.onactivate property.

contentdelete

Occurs when an item is removed from the Content Index. Also available via the ServiceWorkerGlobalScope.oncontentdelete 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 WorkersThe definition of 'ServiceWorkerGlobalScope' in that specification.	Working Draft	Initial definition

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
ServiceWorkerGlobalScope	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
activate event Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
caches Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
clients Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
install event Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
message event Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
notificationclick event	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android No support No	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 27	Safari iOS Full support 11.3	Samsung 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 Full support ≤79 Disabled' Full support ≤79 Disabled' Disabled' From version ≤79: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled).	Firefox ?	IE No support No	Opera ?	Safari Full support 11.1	WebView Android No support No	Chrome 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 11.3	Samsung Internet Android No support No
onactivate Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
onbackgroundfetchabort Experimental'	Chrome Full support 74	Edge No support No	Firefox No support No	IE No support No	Opera Full support 62	Safari No support No	WebView Android No support No	Chrome Android Full support 74	Firefox Android No support No	Opera Android Full support 53	Safari iOS No support No	Samsung Internet Android Full support 11.0
onbackgroundfetchclick Experimental'	Chrome Full support 74	Edge No support No	Firefox No support No	IE No support No	Opera Full support 62	Safari No support No	WebView Android No support No	Chrome Android Full support 74	Firefox Android No support No	Opera Android Full support 53	Safari iOS No support No	Samsung Internet Android Full support 11.0
onbackgroundfetchfail Experimental'	Chrome Full support 74	Edge No support No	Firefox No support No	IE No support No	Opera Full support 62	Safari No support No	WebView Android No support No	Chrome Android Full support 74	Firefox Android No support No	Opera Android Full support 53	Safari iOS No support No	Samsung Internet Android Full support 11.0
onbackgroundfetchsuccess Experimental'	Chrome Full support 74	Edge No support No	Firefox No support No	IE No support No	Opera Full support 62	Safari No support No	WebView Android No support No	Chrome Android Full support 74	Firefox Android No support No	Opera Android Full support 53	Safari iOS No support No	Samsung Internet Android Full support 11.0
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 Full support ≤79 Disabled' Full support ≤79 Disabled' Disabled' From version ≤79: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled).	Firefox ?	IE No support No	Opera ?	Safari ?	WebView Android No support No	Chrome 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 No support No
onfetch Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
oninstall Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
onmessage Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
onmessageerror	Chrome ?	Edge ?	Firefox ?	IE No support No	Opera ?	Safari ?	WebView Android ?	Chrome Android ?	Firefox Android ?	Opera Android ?	Safari iOS ?	Samsung Internet Android ?
onnotificationclick Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
onnotificationclose Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung 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 Full support ≤79 Disabled' Full support ≤79 Disabled' Disabled' From version ≤79: this feature is behind the #service-worker-payment-apps preference (needs to be set to Enabled).	Firefox ?	IE No support No	Opera ?	Safari ?	WebView Android No support No	Chrome 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 No support No
onpush Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
onpushsubscriptionchange Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
onsync Experimental'	Chrome Full support 49	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 49	Chrome Android Full support 49	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 5.0
push event	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
pushsubscriptionchange event	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
registration Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari Full support 11.1	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS Full support 11.3	Samsung Internet Android Full support 4.0
skipWaiting Experimental'	Chrome Full support 40	Edge Full support ≤79	Firefox Full support 44 Notes' Full support 44 Notes' Notes' Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.	IE No support No	Opera Full support 24	Safari No support No	WebView Android Full support 40	Chrome Android Full support 40	Firefox Android Full support 44	Opera Android Full support 24	Safari iOS No support No	Samsung 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

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

ServiceWorkerGlobalScope by Mozilla Contributors is licensed under CC-BY-SA 2.5.