Second, measures your keystroke dynamics and collects comprehensive typing statistics. For example, it measures your typing speed for each individual key, and uses this data to generate random words putting emphasis on the weakest key. The more troubles you have with a particular key, the more you will be  typing it. It means, the generating algorithm will put that letter in every word in the next generated lesson. Your typing skills are re-evaluated after every completed lesson, and the next lesson will be adjusted accordingly.
Created in 2006 by educator Salman Khan, Khan Academy is one of the original free online-learning institutions. With step-by-step video tutorials, you can  learn how to program drawings, animations and games using JavaScript and ProcessingJS, or learn how to create webpages with HTML and CSS. See, especially, Khan's "Hour of Code," designed to introduce students to one hour of computer science and computer programming.
Also, something that I've found is that if you go wrong somewhere instead of mindlessly searching for the error (assuming there are multiple or you don't know the error's location) just start from the beginning and go down seeing that if this works. If you see a break and something disconnects, in all probability that's where the error is. It's all logic.
Here you’ll learn HTML5, CSS3, JavaScript, Databases, React.js, Node.js, and others by networking and joining this nonprofit's community of professionals and students. You’ll even work together on your coding skills so that you can build apps for free. Here’s the catch: You’re learning those skills and building helps to help solve real-world problems. Code is available to nonprofits.