🧠 JavaScript OOP MCQ Test (25 Questions)
🟢 Basic Level
1. What is OOP?
A. Programming with loops
B. Programming with objects
C. Programming with HTML
D. None
👉 Answer: B
2. Which keyword is used to create a class?
A. function
B. object
C. class
D. define
👉 Answer: C
3. What is an object?
A. Function
B. Instance of class
C. Loop
D. Variable
👉 Answer: B
4. Which method runs automatically when object is created?
A. init()
B. start()
C. constructor()
D. create()
👉 Answer: C
5. What does this refer to?
A. Global object
B. Current object
C. Function
D. Class
👉 Answer: B
🟡 Intermediate Level
6. Which keyword is used for inheritance?
A. inherit
B. extends
C. super
D. prototype
👉 Answer: B
7. What is encapsulation?
A. Looping
B. Hiding data
C. Printing output
D. Debugging
👉 Answer: B
8. Private fields are declared using?
A. _
B. $
C. #
D. @
👉 Answer: C
9. What is polymorphism?
A. Same function, different behavior
B. Same output
C. Same variable
D. Same loop
👉 Answer: A
10. Which method overrides parent method?
A. Same name method in child
B. New method
C. Static method
D. Private method
👉 Answer: A
11. What is prototype?
A. Loop
B. Object mechanism for inheritance
C. Function
D. Array
👉 Answer: B
12. What is super used for?
A. Create object
B. Call parent class
C. Delete object
D. Print value
👉 Answer: B
13. Which is correct?
A. JS supports class-based inheritance only
B. JS uses prototype-based inheritance
C. JS has no inheritance
D. None
👉 Answer: B
14. What is a method?
A. Property
B. Function inside object/class
C. Loop
D. Variable
👉 Answer: B
15. Which creates object?
A. new
B. create
C. make
D. object
👉 Answer: A
🔴 Advanced Level
16. Static methods belong to?
A. Object
B. Class
C. Function
D. Array
👉 Answer: B
17. Getters are used to?
A. Set values
B. Get values
C. Delete values
D. Loop values
👉 Answer: B
18. Setters are used to?
A. Get values
B. Set values
C. Print values
D. Loop values
👉 Answer: B
19. What is abstraction?
A. Showing all details
B. Hiding complexity
C. Looping
D. Debugging
👉 Answer: B
20. JavaScript supports multiple inheritance?
A. Yes
B. No
C. Sometimes
D. Only in ES5
👉 Answer: B
21. What is method chaining?
A. Calling methods in sequence
B. Looping
C. Debugging
D. None
👉 Answer: A
22. __proto__ refers to?
A. Class
B. Object reference
C. Loop
D. Variable
👉 Answer: B
23. Classes in JS are?
A. Real classes
B. Syntactic sugar
C. Functions only
D. Variables
👉 Answer: B
24. Which is NOT OOP concept?
A. Inheritance
B. Encapsulation
C. Looping
D. Polymorphism
👉 Answer: C
25. Which is correct syntax?
A. class = Person {}
B. class Person {}
C. Person class {}
D. define class Person {}
👉 Answer: B