This feature has been removed from the Web standards. Though some browsers may still support it, it is in the process of being dropped. Avoid using it and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Important: In modern browsers, this interface has been deprecated. Service worker messages will now use the MessageEvent interface, for consistency with other web messaging features.

The ServiceWorkerMessageEvent interface of the ServiceWorker API contains information about an event sent to a ServiceWorkerContainer target. This extends the default message event to allow setting a ServiceWorker object as the source of a message. The event object is accessed via the handler function of a message event, when fired by a message received from a service worker.

This interface inherits from the Event interface.


Creates a new ServiceWorkerMessageEvent object instance.


Inherits properties from its parent, Event. Read only
Returns the event's data. It can be any data type.
ServiceWorkerMessageEvent.origin Read only
Returns the origin of the service worker's environment settings object.
ServiceWorkerMessageEvent.lastEventId Read only
Represents, in server-sent events, the last event ID of the event source.
ServiceWorkerMessageEvent.source Read only
Returns a reference to the service worker that sent the message.
ServiceWorkerMessageEvent.ports Read only
Returns an array of MessagePort objects.


Inherits methods from its parent, Event.


When the following code is used inside the main thread to set up a message channel between it and a service worker for sending messages between the two, the event object of onmessage will be a ServiceWorkerMessageEvent.

navigator.serviceWorker.ready.then(function(reg) {  
      // set up a message channel to communicate with the SW
      var channel = new MessageChannel();
      channel.port1.onmessage = function(e) {
      mySW =;
      mySW.postMessage('hello', [channel.port2]);


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

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 45.0 44.0 (44.0)[1] No support 24 No support
Deprecated in favour of MessageEvent ? 55.0 (55.0) No support ? No support
Feature Android Android Webview Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support No support (Yes) No support ? No support 45.0
Deprecated in favour of MessageEvent No support No support (Yes) No support ? No support ?

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

See also

Document Tags and Contributors

 Contributors to this page: chrisdavidmills, narohcp, jpmedley
 Last updated by: chrisdavidmills,