Sends messages between two connected MessagePorts in a MessageChannel.

Syntax

Parameters

msg [in]

One of the following:

• JavaScript primitive, such as a string
• object
• Array
• PixelArray object
• ImageData object
• Blob
• File
• ArrayBuffer

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

• HTML5 Web Messaging

Remarks

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

MessagePort

Worker

MessageChannel

Web worker demo