Two new features added: Full Screen API and requestAnimationFrame
Two more requested features have just been added to the site:
The Full Screen API allows browsers to enter a full screen mode for videos or any other given element (great for browser-based games). Note that this spec is still heavily in development.
requestAnimationFrame provides a way to improve the smoothness of script-based animation. It also allows the load on browsers to be reduced when animation plays in background tabs.