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.

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 Standard
# ref-for-dom-websocket-extensions①

Browser compatibility

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