Description
Stop reading about JavaScript. Start writing it.
JS Code Lab is a single interactive HTML file with 100 JavaScript coding challenges — organized by topic, graded instantly, no account needed, no internet required after download.
Write your solution directly in the built-in code editor. Hit Run. Get instant feedback:
✓ Correct Answer — all test cases passed
✗ Try Again — shows exactly what went wrong, with the failing input and expected output
Every challenge runs against real hidden test cases — not just one example, so you actually have to solve it properly.
What’s inside:
- 100 challenges across 10 topics
- Strings (12) · Arrays (14) · Numbers & Math (10) · Objects (11)
- Loops & Algorithms (12) · Higher-Order Functions (8) · Recursion (8)
- Sorting & Searching (7) · ES6+ Features (10) · Async & Promises (8)
- Built-in code editor with syntax highlighting
- Instant pass/fail grading with debug output
- Reference solution + explanation for every challenge
- Search bar to jump to any topic instantly
- Works offline — open in any browser, no login, no subscription
Who is this for?
- JavaScript beginners who want to go beyond tutorials
- Developers preparing for technical interviews
- Students who learn best by doing, not reading
How to use:
Download → Unzip → Open js-code-lab.html in Chrome or Firefox → Start coding.
That’s it. No setup. No account. No expiry.
One file. 100 challenges. Instant feedback.
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