What were some of the key goals and motivations for the HTML5 specification?

There are many good features in HTML5. One of the grate feature is "WebSocket". You can develop real-time application using HTML5 WebSocket.  The WebSocket specification defines an API establishing "socket" connections between a web browser and a server. WebSocket is a protocol providing full-duplex communication channels over a single TCP connection.

SPECIFICATIONS ARE AUDIO & VIDEO APPLICATIONS ARE CREATED IN HTML5