ExtendableMessageEvent

The ExtendableMessageEvent interface of the Service Worker API represents the event object of a message event fired on a service worker (when a message is received on the ServiceWorkerGlobalScope from another context) — extends the lifetime of such events.

This interface inherits from the ExtendableEvent interface.

Constructor

ExtendableMessageEvent()
Creates a new ExtendableMessageEvent object instance.

Properties

Inherits properties from its parent, ExtendableEvent.

ExtendableMessageEvent.data Read only
Returns the event's data. It can be any data type.
ExtendableMessageEvent.origin Read only
Returns the origin of the Client that sent the message.
ExtendableMessageEvent.lastEventId Read only
Represents, in server-sent events, the last event ID of the event source. This is an empty string.
ExtendableMessageEvent.source Read only
Returns a reference to the Client object that sent the message.
ExtendableMessageEvent.ports Read only
Returns the array containing the MessagePort objects representing the ports of the associated message channel.

Methods

Inherits methods from its parent, ExtendableEvent.

Examples

In the below example a page gets a handle to the ServiceWorker object via ServiceWorkerRegistration.active, and then calls its postMessage() function.

// in the page being controlled
if (navigator.serviceWorker) {

  navigator.serviceWorker.register('service-worker.js');

  navigator.serviceWorker.addEventListener('message', (event) => {
    // event is a MessageEvent object
    console.log(`The service worker sent me a message: ${event.data}`);
  });

  navigator.serviceWorker.ready.then( (registration) => {
    registration.active.postMessage("Hi service worker");
  });

}

The service worker can receive the message by listening to the message event:

// in the service worker
addEventListener('message', (event) => {
  // event is an ExtendableMessageEvent object
  console.log(`The client sent me a message: ${event.data}`);

  var promise = self.clients.get(event.source.id).then( (client) => {
    if (client) {
      client.postMessage("Hi client");
    }
  });

  if (event.waitUntil) {
    event.waitUntil(promise);
  }
});

Specifications

Specification Status Comment
Service Workers
The definition of 'ExtendableMessageEvent' 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
ExtendableMessageEvent
Experimental
Chrome Full support YesEdge Full support ≤18Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android Full support YesFirefox Android Full support 45Opera Android ? Safari iOS No support NoSamsung Internet Android Full support Yes
ExtendableMessageEvent() constructor
Experimental
Chrome ? Edge ? Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android ? Firefox Android Full support 45Opera Android ? Safari iOS No support NoSamsung Internet Android ?
data
Experimental
Chrome Full support 51Edge Full support ≤79Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android Full support 51Firefox Android Full support 45Opera Android ? Safari iOS No support NoSamsung Internet Android Full support 5.0
lastEventId
Experimental
Chrome ? Edge Full support 17Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android ? Firefox Android Full support 45Opera Android ? Safari iOS No support NoSamsung Internet Android ?
origin
Experimental
Chrome ? Edge ? Firefox No support NoIE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android ? Firefox Android No support NoOpera Android ? Safari iOS No support NoSamsung Internet Android ?
ports
Experimental
Chrome ? Edge ? Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android ? Firefox Android Full support 45Opera Android ? Safari iOS No support NoSamsung Internet Android ?
source
Experimental
Chrome ? Edge ? Firefox Full support 45
Notes
Full support 45
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR).
IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android ? Firefox Android Full support 45Opera Android ? Safari iOS No support NoSamsung Internet Android ?

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.

See also