While doing research in game development using HTML5, ImpactJS is a framework that is mentioned as being the best to date for making HTML5 games. The great thing is that you can port over HTML5 to mobile platforms using AppMobi, PhoneGap, or Ejecta. You will also learn Node.js and Socket.io in the tutorials.
Here is an extended tutorial for beginners:
The entire playlist http://www.youtube.com/playlist?list=PLAD5A0C028DA09694
With the recent updates of browsers supporting web more W3C standards, it is easier to embed HTML5 videos than before, although you still have to provide your video in multiple codecs such as webm, ogg, and mp4.