javascript.info is an excellent reference for the fundamentals of JS

[Javascript.info](https://javascript.info/) is both a very complete reference, and starts from the very basics, so is friendly to absolute beginners in Javascript. I suggest also that is a more friendly reference for required background knowledge than Crockford's "Javscript the Good Parts" and a better reference than Haverbeke's "Eloquent Javascript". Also it is the only beginner reference I have seen that mentions both debugging _and_ testing! It is as if I have seen a flying pig. After this, there can only be MDN!