This API is available on Firefox or Firefox OS for installed or higher privileged applications.
Summary
The postError method is used to send back an error message to the app that made the activity request.
Syntax
instanceOfMozActivityRequestHandler.postError(message);
Properties
Message- A string describing the error. This string will be used by the system to create a DOMError object.
Specification
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.