The port1
read-only property of the MessageChannel
interface returns the first port of the message channel — the port attached to the context that originated the channel.
Syntax
channel.port1;
Value
A MessagePort
object, the first port of the channel, that is the port attached to the context that originated the channel.
Example
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 a message being sent back from the <iframe>
(using MessagePort.onmessage
), putting it into a paragraph. The handleMessage
method is associated to the port1
to listen 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; }
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'port1' in that specification. |
Living Standard |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
port1 | 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