WebSocket: open event

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

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

js
addEventListener("open", (event) => {});

onopen = (event) => {};

Event type

A generic Event.

Examples

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

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

Specifications

Specification
WebSockets
# dom-websocket-onopen

Browser compatibility

BCD tables only load in the browser

See also