WebSocket: error event

The error event is fired when a connection with a WebSocket has been closed due to an error (some data couldn't be sent for example).


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

addEventListener("error", (event) => {});

onerror = (event) => {};

Event type

A generic Event.


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

// Listen for possible errors
socket.addEventListener("error", (event) => {
  console.log("WebSocket error: ", event);


WebSockets Standard
# dom-websocket-onerror

Browser compatibility

BCD tables only load in the browser

See also