Interactive JavaScript studio

The most beautiful way to get dangerously good at JavaScript.

A full tutorial, 243 in-browser challenges, and 311+ interview answers — built for people who will write tests, not just watch videos.

Start the tutorial Open the editor

Chapters: 52
Challenges: 243
Interview Qs: 311+

A laptop on a navy desk with a yellow mug, ready for a JavaScript session

In-browser editorTests beside youPay once · ₹499

Original notes · No video filler

Playwright-ready JavaScript

Free to practice everything

Lifetime unlock for answers & AI

A real book, not a cheat sheet

Fifty-plus original chapters written so a QA can prepare JavaScript here: language core, async, JSON, HTTP, and assertions — with worked examples and mistakes.

Type until the tests go green

243 editor challenges across 9 courses. Run, fail, fix. Optional AI hints. Solutions stay behind Lifetime if you want the extra edge.

Walk into the interview ready

311+ Q&As, a timed mock, and a cheat sheet. Palindrome to promises, with the same voice as the book.

Curriculum

Nine courses. One studio.

See all practice →

Glass jars and wooden blocks on a studio desk

JavaScript Basics

117

Beginner path: variables through loops, plus numbers — the same core as every strong JS course.

Glowing cubes flowing through a pipeline

Intermediate JavaScript

Array methods, closures, modern syntax, JSON, and regular expressions.

A clock and calendar in navy and gold light

JavaScript Dates

Create, compare, and shift Date values — a topic most practice sites treat as its own course.

Faceted gems and keyed tiles on a teal field

Sets & Maps

Unique collections, unions, and keyed Map storage used in real apps.

Parallel light paths meeting at a horizon

Async JavaScript

Promises, then/catch, async/await, and Promise.all.

Stacked architectural blocks like a class hierarchy

Classes & OOP

Classes, inheritance, getters, and this — the javascript.info object-oriented core.

A maze of nodes with a golden path through it

Algorithms

Interview and freeCodeCamp-style drills: palindrome, chunk, two-sum, and more.

A browser frame with nested cards inside

JavaScript DOM

Selectors, classes, attributes, creating nodes, events, and forms.

Training gear and stacked challenge cards

JavaScript Practice

Mixed fundamentals, array, and object challenges to lock the skills in.

How it works

Read. Type. Walk in ready.

Read

Open the tutorial. One chapter at a time. Predict the result, then look.

Practice

Drop into the matching editor. Make the assertions pass. Keep moving.

Perform

Drill interview Q&A or sit a mock. Leave with a story you can say out loud.

The book

JS Tutorial

52 chapters with examples and QA walkthroughs.

Start reading →

The grill

Interview Q&A

311+ answers, a mock, and a cheat sheet on Lifetime.

Open Q&A →

Who it is for

For QA & SDET interviews

Closures, the event loop, fetch, and JSON — explained in the language of tests, not framework trivia.

For people switching stacks

Start at variables. Finish at async and the DOM. No video pause-and-rewinds; you write the program.

For weekend catch-up

One unit is one scroll. Progress saves on this device. Pick up the next challenge when you are back.

Lifetime Premium

Practice free. Unlock answers once.

Solutions, AI hints, mock scoring, and the interview PDF — ₹499, no subscription.

₹499

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