Do you know JavaScript?

Do you know JavaScript? is an interactive quiz extension to evaluate and improve your JavaScript knowledge. With more than 400 questions spanning beginner to advanced difficulty, it covers current ECMAScript features and real-world behaviors. Each question includes links to documentation and learning resources so you can quickly understand why JavaScript behaves a certain way and close knowledge gaps.

Ideal for learners, interview candidates, and active developers seeking a quick challenge, the extension helps you track progress, prepare for technical interviews, and level up your coding skills. Tackle short quizzes, review explanations, and deepen your understanding of modern JS — write better code and stay current with the language.