So... You want to create an HTML5 game...
Phaser is a fast, free and fun open source framework for Canvas and WebGL powered browser games. You can use Phaser framework to build awesome web based games and for mobile devices as well. Be sure to checkout this amazing framework and their demos at http://phaser.io
Pixi.js is a fast 2d rendering game engine that you can use to build html5 and mobile games. Be sure to checkout this awesome framework at http://www.pixijs.com
Kiwi.js is a fun and friendly open source html5 game engine. Kiwi.js is fast and easy to learn. Be sure to checkout this framework when creating your next game. Visit http://www.kiwijs.org to learn more.
Createjs is a suite of libraries and tools that work together to create rich interactive content on the web. You can also use createjs to create web and mobile based games.
So, next time you want to create the next awesome mobile or html5 game be sure to checkout these awesome game frameworks ;)