WebSocket: open event

{{APIRef("WebSockets API")}}{{AvailableInWorkers}}

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

Syntax

Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}}, or set an event handler property.

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

onopen = (event) => { }

Event type

A generic {{domxref("Event")}}.

Examples

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

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• WebSocket: close event
• WebSocket: error event
• WebSocket: message event
• Writing WebSocket client applications