Pretty much everybody I know that eventually went on to write code for a living starting hacking on little toy projects long before they got anywhere near a com

Pretty much everybody I know that eventually went on to write code for a living starting hacking on little toy projects long before they got anywhere near a computer science course. JS in the browser is a great environment for people to start experimenting and dabbling in the same way that things like LOGO and Basic used to be in the early PC era.