What a program is doing

Almost every program, in any language, is doing four things:

1. Holding values. A number, a name, a list of orders.
2. Changing them. Adding, combining, filtering.
3. Deciding. Doing one thing if something is true and another if it is not.
4. Repeating. Doing the same work for every item in a collection.

That is close to the whole of it. Everything else is detail, tooling, or a way of organising those four so a large program stays understandable.

Why JavaScript

It runs in every browser without you installing anything, which means the exercises in this course run where you are already sitting. The ideas transfer: variables, functions, conditionals and loops look almost the same in Python, Java, C# or Go, and once you have them you are learning a dialect rather than a language.

How this course works

Short explanations, then you write code. The exercises run in your browser and check your work against tests, so a failure tells you what was expected and what your code actually produced. That gap is the useful part.

You will get things wrong constantly. That is not a sign you are bad at this; it is the activity. Professional programmers spend most of their day with something not working.