Due to security issues in WebSockets protocol Firefox and Opera turned off support for WebSockets for their next major releases Firefox 4 and Opera 11. We’ve covered how to enable WebSockets in Opera 11. Firefox 4 Beta 8 will be released with WebSockets support disabled by default, if you want to experiment with WebSockets in Firefox 4, here is how enable it.
Enabling WebSockets in Firefox 4 Beta 8
1. Type about:config in address bar and continue by clicking “I’ll be careful, I promise”
2. Set network.websocket.enabled value to true and set network.websocket.override-security-block preferences to true.
3. Restart Firefox browser.