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.
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 |
---|---|---|
HTML Living Standard The definition of 'port2' in that specification. |
Living Standard |
Browser compatibility
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