A small school for the web

Learn the web by writing it.

Kodingu is a quiet place to learn HTML, CSS, and JavaScript. Read a short lesson, write real code, and check your work in the browser.

Start the HTML course See the catalog

20 HTML lessons, 12 CSS lessons, and 8 JavaScript lessons are open now.

Lesson 01 · A page is a tree

Your first document

Preview

This is a real editor. Change the text and run it.

The method

Small lessons, checked in the browser.

No videos, no account, no AI tutor. You read a page, write a few lines, and the page checks your work.

  1. 01

    Read the idea

    Each lesson teaches one part of the web and shows a real example.

  2. 02

    Write the code

    You edit a working page, stylesheet, or script in the browser. Nothing is uploaded.

  3. 03

    Run the checks

    Each challenge lists what passed and what needs another look.

Catalog

Three languages. One at a time.

All three courses are open now. Start with HTML, then CSS, then JavaScript.

    Beyond the lessons

    When a lesson is not enough.

    Four guided projects ask you to build a whole page. Six extra challenges add one more problem in HTML, CSS, or JavaScript. Both are optional and both stay in this browser.

    Open the projects Try an extra challenge

    What is here

    Built for practice, not for watching.

    Every lesson ends with code you wrote. Progress is stored in this browser, so there is no account to create and nothing to sync.

    Checks that explain
    Each challenge runs against your code and lists every requirement, passed or not.
    A real preview
    Your code renders beside the editor. Run it again after every change.
    Progress that stays yours
    XP, streak, and finished lessons live in localStorage on this device.
    Light and dark
    The theme follows your system at first. The switch in the header remembers your choice.

    Start with one page.

    The first HTML lesson takes about eight minutes.

    Open lesson 01