MessageChannel.port2
The port2
read-only property of the MessageChannel
interface returns 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.
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 (run it live too).
Specifications
Specification | Status | Comment |
---|---|---|
WHATWG HTML Living Standard The definition of 'port2' in that specification. |
Living Standard | No difference from HTML5 Web Messaging. |
HTML5 Web Messaging The definition of 'port2' in that specification. |
Recommendation | W3C version of the spec |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 4 | 41 (41) | 10.0 | 10.6 | 5 |
Available in workers | (Yes) | 41 (41) | (Yes) | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | Firefox OS (Gecko) | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | 4.4 | 4 | 41.0 (41) | (Yes) | 10.0 | 11.5 | 5.1 |
Available in workers | (Yes) | (Yes) | 41.0 (41) | (Yes) | (Yes) | (Yes) | (Yes) |
See also
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/messagechannel/port2