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✨ JavaScript for kids

JavaScript is the language every web page is made of. This track covers let, strings, if, loops, arrays, objects and functions — written and run in the browser, with nothing to set up.

Start the JavaScript track

How this track is kept honest

Code runs in a sandboxed worker with the network switched off, and the console output a lesson claims comes out of the same formatter the app itself uses — so a lesson can never promise [1,2,3] while the screen shows something else.

Best after Python, or after any first language. No installing, no setup — it runs in a browser tab.

How it starts

JavaScript says console.log instead of print. Lines usually end with a semicolon ;. Everything else feels familiar.

The full JavaScript syllabus

10 units and 53 lessons, in the order they are played. Each unit has a page of its own with every explanation in it, the code samples and what they print, and a few questions to try.

Unit 1: Hello, JavaScript

Same ideas, new spelling

  1. console.log
  2. let & const
  3. Curly Braces
  4. And, Or, Not
  5. Loop Master

Unit 2: Functions & Loops

Teach the computer new words

  1. Making Functions
  2. Sending Answers Back
  3. Arrow Functions
  4. Keep Going Until
  5. Function Factory

Unit 3: Arrays

Lists that do tricks

  1. Lists, JavaScript Style
  2. Growing Arrays
  3. Walking Through
  4. Array Superpowers
  5. Array Master

Unit 4: Words, Objects & Maths

Model real things

  1. Text Tools
  2. Objects
  3. Objects in Arrays
  4. Numbers & Maths
  5. Data Wrangler

Unit 5: Types & Choices

What kind of thing is this?

  1. What Type Is It?
  2. Changing Types
  3. Truthy & Falsy
  4. switch
  5. Type Detective

Unit 6: Scope & Shortcuts

Where names live

  1. Where Names Live
  2. Default & Extra Arguments
  3. Spreading Out
  4. Unpacking
  5. Functions That Remember
  6. Shortcut Champion

Unit 7: Classes

Blueprints for things

  1. Your First Class
  2. Methods & this
  3. Getters, Setters & Static
  4. Inheritance
  5. Many Shapes
  6. Class Champion

Unit 8: Sets, Maps & JSON

Better boxes for data

  1. Sets
  2. Maps
  3. Sorting & Object Tools
  4. JSON
  5. Collection Champion

Unit 9: When Things Go Wrong

Catch it, do not crash

  1. Reading Errors
  2. throw & finally
  3. Your Own Error Types
  4. Checking with Patterns
  5. Safety Net

Unit 10: Waiting & The Web

Code that finishes later

  1. Callbacks
  2. Promises
  3. async & await
  4. One Thing At A Time
  5. The Page
  6. Web Ready

Other things to learn

Start learning — units 1–2 are free