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JavaScript Beginner

Variables, types, functions, control flow, arrays and objects.

3 lessons 7 tasks ⚡ Live compiler

📚 Lessons

Declare with let and const. Core types: number, string, boolean, null, undefined, object and array.

const name = 'Ada';
let age = 36;
console.log(name + ' is ' + age);
console.log(typeof age, typeof name);

Functions package logic. Use if/else, for and while for control flow.

function factorial(n) {
  let r = 1;
  for (let i = 2; i <= n; i++) r *= i;
  return r;
}
console.log('5! =', factorial(5));

Arrays hold ordered lists; objects hold key/value pairs. Access with [] and ..

const user = { name: 'Mara', roles: ['admin', 'editor'] };
console.log(user.name);
console.log(user.roles[0]);
console.log(user.roles.length);

Code runs live in a sandboxed frame, rendered by your browser.

7 tasks across 3 pages — multiple-choice and fill-in (type the answer). Score 70% or higher to earn your certificate.

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