JavaScript Interview Questions

01What is JavaScript?

02What are the data types in JavaScript?

03What is the difference between let, const, and var?

04What is hoisting?

05What is the DOM?

06What is an event listener?

07What is the difference between == and ===?

08What is NaN?

09Explain undefined vs null.

10How do you add an element to an array?

11What is a closure?

12What is an arrow function?

13What does 'use strict' do?

14How do you check the type of a variable?

15What is the purpose of the this keyword?

16What are template literals?

17What is JSON?

18How do you convert a string to a number?

19What is a promise?

20What is the spread operator?

21What is object destructuring?

22How do you empty an array?

23What is the difference between map() and forEach()?

24What is a callback function?

25What is strict mode?

26How does setTimeout() work?

27How does setInterval() work?

28What is DOM delegation?

29What is the purpose of Array.isArray()?

30What does the isNaN() function do?

31Explain the difference between document.getElementById and document.querySelector.

32What is event bubbling?

33What is event capturing?

34How do you prevent default event behavior?

35How do you stop event propagation?

36What are default parameters?

37What is the difference between innerHTML and innerText?

38How do you parse a JSON string?

39How do you convert an object to a JSON string?

40What is the window object?

41What is a module in JavaScript?

42What is the Math object?

43How do you generate a random number?

44What is the Date object?

45How do you get the current time?

46What is local storage?

47What is session storage?

48What is a cookie in JavaScript?

JavaScript Interview Questions

01What is JavaScript?

02What are the data types in JavaScript?

03What is the difference between let, const, and var?

04What is hoisting?

05What is the DOM?

06What is an event listener?

07What is the difference between == and ===?

08What is NaN?

09Explain undefined vs null.

10How do you add an element to an array?

11What is a closure?

12What is an arrow function?

13What does 'use strict' do?

14How do you check the type of a variable?

15What is the purpose of the this keyword?

16What are template literals?

17What is JSON?

18How do you convert a string to a number?

19What is a promise?

20What is the spread operator?

21What is object destructuring?

22How do you empty an array?

23What is the difference between map() and forEach()?

24What is a callback function?

25What is strict mode?

26How does setTimeout() work?

27How does setInterval() work?

28What is DOM delegation?

29What is the purpose of Array.isArray()?

30What does the isNaN() function do?