MessageEvent: lastEventId property

Baseline Widely available

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

Note: This feature is available in Web Workers.

The lastEventId read-only property of the MessageEvent interface is a string representing a unique ID for the event.

Value

A string representing the ID.

Examples

js
myWorker.onmessage = (e) => {
  result.textContent = e.data;
  console.log("Message received from worker");
  console.log(e.lastEventId);
};

Specifications

Specification
HTML Standard
# dom-messageevent-lasteventid-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.