The MessageChannel
interface of the Channel Messaging API allows us to create a new message channel and send data through it via its two MessagePort
properties.
MessageChannel.port1
Read only
MessageChannel.port2
Read only
MessageChannel()
Returns a new MessageChannel
object with two new MessagePort
objects.
In the following code block, you can see a new channel being created using the MessageChannel()
constructor. When the <iframe>
has loaded, we pass MessageChannel.port2
to the <iframe>
using MessagePort.postMessage
along with a message. The handleMessage
handler then responds to the message being sent back from the <iframe>
(using MessagePort.onmessage
), by putting it into a paragraph.
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 (run it live too).
Specification | Status | Comment |
---|---|---|
WHATWG HTML Living Standard The definition of 'MessageChannel' in that specification. | Living Standard | No difference from HTML5 Web Messaging. |
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|---|
Basic support | 4 | (Yes) | 41 (41) | 10.0 | 10.6 | 5 |
Available in workers | (Yes) | ? | 41 (41) | (Yes) | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Edge | Firefox Mobile (Gecko) | Firefox OS (Gecko) | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|---|
Basic support | 4.4 | 4 | (Yes) | 41.0 (41) | (Yes) | 10.0 | 11.5 | 5.1 |
Available in workers | (Yes) | (Yes) | ? | 41.0 (41) | (Yes) | (Yes) | (Yes) | (Yes) |
© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/MessageChannel