Web Application APIs

Canvas 2D Context
Contacts API
CSS Selectors Level 1 and CSS Selectors Level 2
Data Caching and Serving
File APIs
Geolocation API
Indexed Database API
Form Based Media Capture
Media Capture API
Messaging API
compatible with JSON and RDF
Server-Sent Event Source
Web Messaging
Web Sockets
Web Storage
Web Workers
XMLHttpRequest Level 2 and XMLHttpRequest Level 2