[bira]

Start with Udacity, it's university-grade material thought by college professors and/or highly experienced professionals while Codecademy (at the moment) is more like an interactive tutorial that walk you through how to do simple, practical stuff like building an html work, how to use CSSs etc.

You can benefit from both, depending on what you want to build and at what stage of your project you are in.

I would start with Udacity, but be advised it's going to be no cakewalk.

I have no deep experience with MitX (nor Coursera) though I checked them out briefly and they seem to provide insane quality considering they come with no price tags.