BroadcastChannel: postMessage() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2022.

We’d love to hear your thoughts on the next set of proposals for the JavaScript language. You can find a description of the proposals here.
Please take two minutes to fill out our short survey.

Note: This feature is available in Web Workers.

The postMessage() method of the BroadcastChannel interface sends a message, which can be of any kind of Object, to each listener in any browsing context with the same origin. The message is transmitted as a message event targeted at each BroadcastChannel bound to the channel.

Syntax

js
postMessage(message)

Parameters

message

Data to be sent to the other window. The data is serialized using the structured clone algorithm. This means you can pass a broad variety of data objects safely to the destination window without having to serialize them yourself.

Return value

None.

Exceptions

InvalidStateError DOMException

Thrown if the BroadcastChannel has already been closed.

DataCloneError DOMException

Thrown if any part of the input data is not serializable.

Specifications

Specification
HTML
# dom-broadcastchannel-postmessage-dev

Browser compatibility

See also