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.

Syntax

var extensions = aWebSocket.extensions;

Value

A DOMString.

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'WebSocket: extensions' in that specification.
Living Standard Initial definition

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
extensionsChrome Full support YesEdge Full support 12Firefox Full support 8IE ? Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support 8Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android ?

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown

Document Tags and Contributors

Contributors to this page: mdnwebdocs-bot, sideshowbarker, fscholz, Claas
Last updated by: mdnwebdocs-bot,