Bite-sized, tested and vetted
- [Free] Server-side quiz 1 (122 questions): random - default
- [Free] Browser-side quiz (19 questions): random - default
- [Paid] Basics (73 exercises): random - default
- [Paid] OOP (43 exercises): random - default
- [Paid] Promises (41 exercises): random - default
Other
- Easy syntax exercises on W3Schools (67 exercises)
- Browser-side quiz on W3Schools (25 questions)
- JavaScript basics on JSchallenger (101 exercises)
- JavaScript DOM on JSchallenger (19 exercises)
- Random JavaScript exercises on JSchallenger (80 exercises)
- LeetCode (1000+ problems)
- Exercism (141 exercises)
- Math-related problems on Project Euler (841 problems)
- Edabit (2500+ challenges)
- Codewars (6000+ exercises)
- JS Is Weird (25 questions)
- JavaScript Quiz (10 questions)
- CodesCracker (several quizzes)
- JavaTpoint (several quizzes)