On Client side
- Chrome 4.0 supports Websockets.
- Safari 5.0.2 supports them too
- Firefox 4.0 ships with support for WebSockets disabled. to enable it see
- Opera 11 ships with support disabled to re-enable it see
- IE9 does not support them, however an add-on offers experimental support
For other browsers it's not so clear.
On Server side it depends on which language you use.
In Java/JEE :
- Jetty 7.0 supports it (Very easy to use),
- GlassFish 3.0 (very low level and sometimes complex), Glassfish 3.1 has new refactored Websocket Support which is more developer friendly and
- Caucho Resin 4.0.2 (not yet tried) too.
Some other Java implementations are :
- Kaazing Gateway,
- jWebscoket,
- Netty and
- xLightWeb.
In PHP :
- phpwebsocket.
In node.js :
- Socket.io : Socket.io also has serverside ports for Python, Java, Google GO, Rack.