It's time to apply the skills you've learned so far to build a mini-game: an interactive Tic Tac Toe game in the browser. These lessons will incorporate object-oriented programming and DOM manipulation.
By applying your skills in this context, you'll get a feel for how to organize your code and your files. You're also going to see how HTML, CSS, and JavaScript can work together to produce an application, without relying on outside tools or frameworks.
These lessons are taught by JavaScript consultant Mike Dane, who holds a Masters degree in computer science and has worked for Lockheed Martin.