Learn JavaScript at the Codeacademy

Created by a pair of Columbia students, the Codeacademy offers courses on JavaScript using a series of simple steps that build on each other, while offering plenty of encouragement and feedback to the learner. The site has gotten a lot of activity since its launch in early September, reaching over half a million coders-to-be. Codeacademy plans to offer courses for other programming languages and will include user-submitted courses as well.

Codeacademy has been featured in the New York Times and other publications. All courses are offered for free.