Javascript Challenges are a set of puzzles designed to teach Javascript by creating a set of active learning / problem-solving puzzles -- learning-by-doing, rather than learning-by-watching-videos. The challenges are designed to be fun, and also to highly limit the scope of each problem, so that learners can tackle one aspect of Javascript at a time.
For a Grasshopper version, see: Grasshopper Challenges
(To work with this in Glitch, make sure to hit the "Change URL" button above and set your URL to /challengesA.html or such!)