WebSocket: open event

The open event is fired when a connection with a WebSocket is opened.

Bubbles No
Cancelable No
Interface Event
Event handler property onopen


// Create WebSocket connection.
const socket = new WebSocket('ws://localhost:8080');

// Connection opened
socket.addEventListener('open', (event) => {
  socket.send('Hello Server!');


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

Browser compatibility

BCD tables only load in the browser

See also