Web/API/WebSocket/WebSocket

The WebSocket() constructor returns a new WebSocket object.

Syntax

var aWebSocket = new WebSocket(url [, protocols]);

Parameters

url

The URL to which to connect; this should be the URL to which the WebSocket server will respond.

protocols Optional

Either a single protocol string or an array of protocol strings. These strings are used to indicate sub-protocols, so that a single server can implement multiple WebSocket sub-protocols (for example, you might want one server to be able to handle different types of interactions depending on the specified protocol). If you don't specify a protocol string, an empty string is assumed.

Exceptions thrown

SECURITY_ERR

The port to which the connection is being attempted is being blocked.

SyntaxError

The URL is invalid.

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'the WebSocket constructor' in that specification.	Living Standard

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
WebSocket() constructor	Chrome Full support Yes	Edge Full support ≤79	Firefox Full support 7 Full support 7 No support 4 — 7 Notes' Notes' Parameter protocols not supported.	IE ?	Opera Full support Yes	Safari ?	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 7	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support Yes

Legend

Full support  

Full support

Compatibility unknown  

Compatibility unknown

See implementation notes.'

See implementation notes.

WebSocket() by Mozilla Contributors is licensed under CC-BY-SA 2.5.