Coursera is an education platform that partners with top universities and organizations worldwide, to offer courses online for anyone to take, for free.
Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. Subjects include math, science, computer programming, history, art history, economics, and more.
W3Schools is a web developers site, with tutorials and references on web development languages such as HTML, CSS, JavaScript, PHP, SQL, and JQuery, covering most aspects of web programming.
