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


The source property returns a MozActivityOptions object, which provides information about the activity request.


navigator.mozSetMessageHandler('activity', function(aRequestHandler) {
  var activityOptions = aRequestHandler.source;
  if ( == 'share') {
  } else if ( == 'view') {


Return a MozActivityOptions object.


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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 Contributors to this page: chrisdavidmills, fscholz, jsx, kscarfone, Sheppy, mounirlamouri, Jeremie
 Last updated by: chrisdavidmills,