ServiceWorkerContainer: message event

The message event is used in a page controlled by a service worker to receive messages from the service worker.

Bubbles No
Cancelable No
Interface MessageEvent
Event handler property onmessage


In this example the service worker get the client's ID from a fetch event and then sends it a message using Client.postMessage:

// in the service worker
async function messageClient(clientId) {
    const client = await clients.get(clientId);
    client.postMessage('Hi client!');

addEventListener('fetch', (event) => {
    event.respondWith(() => {
      // ...

The client can receive the message by listening to the message event:

// in the page being controlled
navigator.serviceWorker.addEventListener('message', (message) => {


Specification Status
Service Workers
The definition of 'message' in that specification.
Working Draft

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
message eventChrome Full support 40Edge Full support 17
Full support 17
Full support 16
Disabled From version 16: this feature is behind the Enable service workers preference.
Firefox Full support 44
Full support 44
Notes Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
IE No support NoOpera Full support 27Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support 11.3Samsung Internet Android Full support 4.0


Full support  
Full support
No support  
No support
See implementation notes.
See implementation notes.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also