MozActivityRequestHandler Redirect 1

This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

This API is available on Firefox or Firefox OS for installed or higher privileged applications.


The MozActivityRequestHandler interface allows apps that handle activities to access and interact with the request made by a third party app that tries to delegate an activity.

To handle activities, an application has to register a handler to the system message activity using navigator.mozSetMessageHandler(). The callback that is passed to navigator.mozSetMessageHandler() will be called with a MozActivityHandler object in parameter when the system message is of the type activity.

Interface overview

interface MozActivityRequestHandler
  readonly attribute MozActivityOptions source;

  void postResult(object result);
  void postError(DOMString error);


MozActivityRequestHandler.source Read only
A MozActivityOptions object containing all the information about the current activity request.


Allows to send back a success response to the app that initiated the activity.
Allows to send back an error response to the app that initiated the activity.


Web Activities is not part of any specification. However, it has some overlap with the proposed Web Intents specification. Mozilla actually proposed Web Activities as a counter proposal to Web Intents. For more information about this, see discussion on the Web Intents Task Force ML.

See also

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Last updated by: Sheppy,