MessageEvent()

The MessageEvent() constructor creates a new MessageEvent object instance.

Syntax

new MessageEvent(type)
new MessageEvent(type, init)

type

A string indicating the type of MessageEvent that will be created. Some of the more common types are: message, messageerror, connect.

init Optional

A dictionary object that can contain the following properties:

data: The data you want contained in the MessageEvent. This can be of any data type, and will default to null if not specified.
origin: A USVString representing the origin of the message emitter. This defaults to an empty string ("") if not specified.
lastEventId: A DOMString representing a unique ID for the event. This defaults to an empty string ("") if not specified.
source: An MessageEventSource (which can be a WindowProxy, MessagePort, or ServiceWorker object) representing the message emitter. This defaults to null if not set.
ports: An array of MessagePort objects representing the ports associated with the channel the message is being sent through (where appropriate, e.g. in channel messaging or when sending a message to a shared worker). This defaults to an empty array ([]) if not specified.

var myMessage = new MessageEvent('message', {
  data : 'hello'
});

Specification
HTML Standard # the-messageevent-interface:dom-event-constructor

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	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`MessageEvent`	1	12	26	9	≤12.1	4	4.4	18	26	≤12.1	3.2	1.0