< WebAPI



Presentation API enables web content to access external presentation-type displays and use them for presenting web content. With this API, web page can initiate and control an presentation request.

For retrieving available devices information, please refer to Presentation Device Info API.


Use case


  • For 1-UA user agent, three preferences "dom.presentation.enabled", "dom.presentation.controller.enabled", and "dom.presentation.receiver.enabled" need to be set to true.
  • For 2-UAs controlling user agent, two preferences "dom.presentation.enabled" and "dom.presentation.controller.enabled" need to be set to true.
  • For 2-UAs receiving user agent, two preferences "dom.presentation.enabled" and "dom.presentation.receiver.enabled" need to be set to true.


  • WebIDL
  • No UI support for defaultRequest.


  • WebIDL
  • support URL with http:// protocol scheme to open web page in private browsing mode
  • support URL with app:// protocol scheme to launch an packaged app installed on target B2G device
  • only available in controlling browsing context




  • WebIDL
  • only available in receiving browsing context


  • WebIDL
  • only available in controlling browsing context


Here is the high-level architecture overview of Presentation API.

Architecture overview of Presentation API

WebIDL Implementation

Core Service

  • Maintain the session state and app-to-app transportation channel
  • Handle the session setup / reconnect / terminate procedure
  • Live in chrome process
    • except for DataChannelTransportBuilder and DataChannelTransport
  • Detail at WebAPI/PresentationAPI:CoreService

Device Manager

  • Load registered device provider at start-up automatically
  • Provide device list and firing availability event
  • Live in chrome process

Device Provider

  • Implement device discovery mechanism
  • Handle control channel setup procedure
  • Live in chrome process

Browser/System UI Glue

  • Handle device selection and application launch
  • Live in chrome process

Development Plan

Basic Functionalities

Advanced Functionalities

  • Enable 1-UA mode for DIAL app to increase device compatibility
  • Support different URL scheme, e.g. data, file
  • Support multiple session (n:1) to support wider user scenario, e.g. multi-player game. (Bug 1195605 (NEW))