WebSocket: close event

The close event is fired when a connection with a WebSocket is closed.

Bubbles No
Cancelable No
Interface CloseEvent
Event handler property onclose


You might want to know when the connection has been closed so that you can update the UI or, perhaps, save data about the closed connection. Given that you have a variable called exampleSocket that refers to an opened WebSocket, this handler would handle the situation where the socket has been closed.

exampleSocket.addEventListener('close', (event) => {
  console.log('The connection has been closed successfully.');

You can perform the same actions using the event handler property, like this:

exampleSocket.onclose = function (event) {
  console.log('The connection has been closed successfully.');


Specification Status
HTML Living Standard
The definition of 'WebSocket close' in that specification.
Living Standard

Browser compatibility

BCD tables only load in the browser

See also