WebSocket: extensions property

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 WebSocket.extensions read-only property returns the extensions selected by the server. This is currently only the empty string or a list of extensions as negotiated by the connection.

Value

A string.

Specifications

Specification
WebSockets
# ref-for-dom-websocket-extensions①

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
extensions

Legend

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Full support
Full support