CloseEvent: reason 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.

The reason read-only property of the CloseEvent interface returns the WebSocket connection close reason the server gave for closing the connection; that is, a concise human-readable prose explanation for the closure.

Value

A string.

Examples

The following example prints the value of reason to the console.

js
WebSocket.onclose = (event) => {
  console.log(event.reason);
};

Specifications

Specification
WebSockets Standard
# ref-for-dom-closeevent-reason②

Browser compatibility

BCD tables only load in the browser

See also

  • RFC 6455 (the WebSocket Protocol specification)