CodingNeed.
JavaScript · Beginner

JavaScript from zero

From your first instruction to a working expense summary. No setup or previous coding needed.

Prerequisite: None · 99 minutes of guided study

11 published lessons, from first principles to a small project.

Open interactive course →

1 · First steps

  1. Your first instruction

    A program is a sequence of instructions.

    6 min →
  2. Give values a name

    Variables keep values available for later instructions.

    7 min →
  3. Calculate a total

    Expressions calculate values.

    8 min →

2 · Make decisions

  1. Choose a path

    Conditions choose which instructions run.

    8 min →
  2. Read and fix an error

    Errors are clues you can investigate.

    7 min →

3 · Work with collections

  1. Reuse a function

    Functions turn inputs into outputs.

    8 min →
  2. Keep an ordered list

    Arrays store values in order, starting at index zero.

    8 min →
  3. Repeat with a loop

    A loop applies an operation to each item.

    10 min →

4 · Build useful programs

  1. Select matching items

    Filtering keeps items that meet a rule.

    9 min →
  2. Describe a real thing

    Objects group related properties.

    8 min →
  3. Project · Expense summary

    Combine loops, objects, conditions, and functions.

    20 min →