W3Schools is the world's largest web development site and offers free coding tutorials and reference materials for learning almost every aspect of web programming. Another non-profit company, Khan Academy, offers excellent resources for beginners to learn how to code for free. Coderbyte is a developer site that offers short introductory courses in different technologies, plus a library of code challenges to help you prepare for technical interviews. With bite-sized lessons, unlockable achievements and interactive quizzes, it makes learning to code fun, and it's free to download.
As you learn, you'll encounter in-browser challenges that require practical application of what you're learning. If you need help, there is a community forum to discuss assignments and ask for feedback from peers. Each course has a set of explanations and instructions, along with a code editor for students to practice their knowledge. You can also take the quizzes and exercises to determine your level of knowledge and decide which topic to learn next.