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Hectal

JavaScript · the language of the web

Make the web move,
from your first line to the event loop.

Start from zero: no programming experience needed, and every word is explained in plain English. You will learn values and types, control flow, functions and closures, arrays and objects, this and classes, the DOM and events, asynchronous code and the event loop, fetch and browser APIs, modules and tooling, errors and testing, and the deep parts interviews test. Every example runs live on the page with a console, every feature is tagged with the ECMAScript version that added it, and every phase ends with exercises your browser checks automatically.

Start from zero The full roadmap
Phases
16
Topics
118
Hours
47
Diagrams
130
Exercises
765

By the end you can

What this course makes you able to do

  • Write JavaScript programs confidently: values, types, control flow and functions
  • Use arrays, objects, classes and closures the way professionals do
  • Build interactive pages with the DOM and events, safely
  • Predict async code: timers, promises, async/await and the event loop
  • Fetch data, use browser APIs and structure code with modules and tooling
  • Debug, test and explain JavaScript in depth, ready for interviews

Beginner → Advanced

The curriculum, by level

Beginner
  1. 0Start Here: What JavaScript Is4 topics · ~84 min
  2. 1Values, Types and Variables6 topics · ~2 h
  3. 2Operators and Control Flow7 topics · ~3 h
  4. 3Functions9 topics · ~4 h
  5. 4Strings, Numbers and Dates6 topics · ~3 h
  6. 5Arrays10 topics · ~3 h
  7. 6Objects7 topics · ~3 h
Intermediate
  1. 7this, Prototypes and Classes8 topics · ~4 h
  2. 8The DOM8 topics · ~3 h
  3. 9Events8 topics · ~3 h
  4. 10Asynchronous JavaScript8 topics · ~3 h
  5. 11Network and Browser APIs8 topics · ~3 h
  6. 12Modules and Tooling6 topics · ~3 h
  7. 13Errors, Debugging and Testing6 topics · ~2 h
Advanced
  1. 14Advanced Language9 topics · ~3 h
  2. 15Patterns, Security and Interviews8 topics · ~4 h

Where should I start?

Pick a path for your goal

Complete beginner

Never programmed before. Start here: every word is explained.

  1. 10 · Start Here: What JavaScript Is
  2. 21 · Values, Types and Variables
  3. 32 · Operators and Control Flow
  4. 43 · Functions
  5. 55 · Arrays
  6. 66 · Objects

Front-end developer

You know the basics and want to build real interactive apps.

  1. 17 · this, Prototypes and Classes
  2. 28 · The DOM
  3. 39 · Events
  4. 410 · Asynchronous JavaScript
  5. 511 · Network and Browser APIs
  6. 612 · Modules and Tooling

Advanced and interviews

You write JavaScript daily and want the deep parts.

  1. 13 · Functions
  2. 210 · Asynchronous JavaScript
  3. 314 · Advanced Language
  4. 415 · Patterns, Security and Interviews