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postMessage method

Sends messages between two connected MessagePorts in a MessageChannel.

HTML5 Web Messaging



MessagePort.postMessage(msg, ports);


msg [in]

One of the following:

postMessage cannot send a function as a message.

ports [in, optional]

A JavaScript array of MessagePort objects to send to the receiving MessagePort.

Return value

This method does not return a value.

Standards information


When you create a new MessageChannel object, it has two connected MessagePort objects that can only send and receive messages between them. If the ports parameter is supplied but contains errors, an InvalidStateError exception is thrown. Sending a message containing an un-supported object (such as a function), a DataCloneError exception is thrown.

For more info, see MessageChannel for a working messaging demo.

See also

Web worker demo