Web/API/MessageEvent/ports

The ports read-only property of the MessageEvent interface is 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).

Syntax

var myPorts = messageEvent.ports;

Value

An array of MessagePort objects.

Example

onconnect = function(e) {
  var port = e.ports[0];

  port.addEventListener('message', function(e) {
    var workerResult = 'Result: ' + (e.data[0] * e.data[1]);
    port.postMessage(workerResult);
  });

  port.start(); // Required when using addEventListener. Otherwise called implicitly by onmessage setter.
}

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'ports' in that specification.	Living Standard	Initial definition

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
ports	Chrome Full support 1	Edge Full support 12	Firefox Full support 4	IE Full support 9	Opera Full support Yes	Safari Full support 4	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support Yes	Opera Android Full support Yes	Safari iOS Full support 3	Samsung Internet Android Full support Yes

Legend

Full support  

Full support

See also

• ExtendableMessageEvent — similar to this interface but used in interfaces that needs to give more flexibility to authors.

MessageEvent.ports by Mozilla Contributors is licensed under CC-BY-SA 2.5.