JavaScript
The programming language that makes web pages interactive.
1. Introduction to JavaScript
What JavaScript does, how it runs inside a page, and why these examples write to the page instead of a console.
2. Variables (let, const, var)
Storing values with let and const, and why const should be your default, not let.
3. Data Types
Strings, numbers, booleans, arrays, and objects, the handful of types nearly everything in JavaScript is built from.
4. Operators
Arithmetic, comparison, and logical operators, and why === beats == almost every time.
5. Conditionals (if / else)
Branching logic with if, else if, and else, the exact pattern that decides which path code takes.
6. Loops (for / while)
Repeating code with for loops and while loops, and when to reach for each one.
7. Functions
Packaging reusable logic with function declarations and arrow functions, two syntaxes, the same underlying idea.
8. Arrays
Ordered lists of values, and the methods to work with them, map and filter especially.
9. Objects
Grouping related data as key/value pairs, and the two ways to read a value back out.
10. DOM Manipulation
Reading and changing the page itself with document methods, how JavaScript actually makes a static page interactive.