If you don’t know WebSockets are disabled by Opera and Firefox for their Opera 11 and Firefox 4 major releases as vulnerabilities found in WebSockets Protocol. Recently Opera 11 got WebSockets support and expected to release final version with WebSockets, Firefox 4 final version also to release with WebSockets support.
How to Check Whether a Browser Supports WebSockets or Not?
“WebSockets sets up one TCP connection and confirms that server can speak WebSocket by doing special handshake, after which the server and client can send text messages over the connection at will, resulting in faster communication” says Opera.
Here is how to re-enable WebSockets in Opera 11 if you really want.
1. Open Opera browser, type or paste opera:config#Enable%20WebSockets in the address bar and press enter.
2. Select or tick mark against “Enable WebSockets” under User Prefs .
3. Click ‘Save’ button and restart Opera browser.