MessageEvent: ports property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2015.

Note: This feature is available in Web Workers.

The ports read-only property of the MessageEvent interface is an array of MessagePort objects containing all MessagePort objects sent with the message, in order.

Value

An array of MessagePort objects.

Examples

js
onconnect = (e) => {
  const port = e.ports[0];

  port.addEventListener("message", (e) => {
    const workerResult = `Result: ${e.data[0] * e.data[1]}`;
    port.postMessage(workerResult);
  });

  port.start(); // Required when using addEventListener. Otherwise called implicitly by onmessage setter.
};

Specifications

Specification
HTML Standard
# dom-messageevent-ports-dev

Browser compatibility

BCD tables only load in the browser

See also

  • ExtendableMessageEvent — similar to this interface but used in interfaces that needs to give more flexibility to authors.