JavaScript Quiz
Master the language of the web
Practice JavaScript with 106 questions spread across 4 difficulty levels, roughly 145 minutes of practice in total. Every question comes with a written explanation, so a wrong answer teaches you something. Useful for interview preparation, for checking your own level before taking on a project, or just for finding the gaps in what you know.
Choose your difficulty level
JavaScript Fundamentals
Variables, types, functions and arrays — the basics, checked by reading code rather than reciting definitions.
JavaScript Advanced Concepts
Scope, async behaviour, array methods and equality — the everyday JavaScript that decides whether code works or merely appears to.
JavaScript Advanced Concepts
Closures, prototypes, coercion and async behaviour — worked through code rather than definitions, the way a real technical screen does it.
JavaScript Expert Level
Event loop ordering, closures, coercion and prototypes — the questions that actually separate senior candidates in a technical screen.