The port2
read-only property of the MessageChannel
interface returns the second port of the message channel — the port attached to the context at the other end of the channel, which the message is initially sent to.
Note: This feature is available in Web Workers.
Syntax
channel.port2;
Value
A MessagePort
object representing the second port of the channel, the port attached to the context at the other end of the channel.
Example
In the following code block, you can see a new channel being created using the MessageChannel.MessageChannel
constructor. When the IFrame has loaded, we pass port2
to the IFrame using MessagePort.postMessage
along with a message. The handleMessage
handler then responds to a message being sent back from the IFrame (using MessagePort.onmessage
), putting it into a paragraph. MessageChannel.port1
is listened to, to check when the message arrives.
var channel = new MessageChannel();
var para = document.querySelector('p');
var ifr = document.querySelector('iframe');
var otherWindow = ifr.contentWindow;
ifr.addEventListener("load", iframeLoaded, false);
function iframeLoaded() {
otherWindow.postMessage('Hello from the main page!', '*', [channel.port2]);
}
channel.port1.onmessage = handleMessage;
function handleMessage(e) {
para.innerHTML = e.data;
}
For a full working example, see our channel messaging basic demo on Github ([[../../../../../../../mdn.github.io/dom-examples/channel-messaging-basic/index|run it live too]]).
Specifications
Specification | Status | Comment |
HTML Living StandardThe definition of 'port2' in that specification. | Living Standard |
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 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
port2
|
Chrome
Full support 4 |
Edge
Full support 12 |
Firefox
Full support 41 |
IE
Full support 10 |
Opera
Full support 10.6 |
Safari
Full support 5 |
WebView Android
Full support 4.4 |
Chrome Android
Full support 18 |
Firefox Android
Full support 41 |
Opera Android
Full support 11 |
Safari iOS
Full support 5.1 |
Samsung Internet Android
Full support 1.0 |
Legend
- Full support
- Full support
See also
MessageChannel.port2 by Mozilla Contributors is licensed under CC-BY-SA 2.5.