Intro

The Broadcast Channel API allows basic communication between browsing contexts (that is, windows, tabs, frames, or iframes) and workers on the same origin.

By creating a BroadcastChannel object, you can receive any messages that are posted to it. You don't have to maintain a reference to the frames or workers you wish to communicate with: they can “subscribe” to a particular channel by constructing their own BroadcastChannel with the same name, and have bi-directional communication between all of them.  

Implementation

This library implements:

• Blocks
  • BroadcastChannel
    • ChannelName
    • OnMessage
    • OnMessageError
• Methods
  • BroadcastChannel_PostMessage
    • WidgetID
    • Message
  • BroadcastChannel_Properties
    • WidgetID
    • ChannelName (Out)

Usage

The BroadcastChannel block represents a named channel that any browsing context of a given origin can subscribe to. It allows communication between different documents (in different windows, tabs, frames or iframes) of the same origin. Messages are broadcasted via a message event fired at all BroadcastChannel objects listening to the channel.

Implement the OnMessage to handle incoming messages

Use the BroadcastChannel_PostMessage method to send a message to a channel.

The WidgetID is the name of the block, and is mandatory input for the post message method.

Use cases

Some use cases for broadcast channels include:

• Detect user actions in other tabs
• Know when a user logs into an account in another window/tab.
• When the user uploads a photo in one window, pass it around to other open pages pop ups.

Check out the demo app of an online store where if you add a product to the cart all open tabs will update the cart automatically.

Even Amazon cant do this ;)