Javascript Developer Interview Questions & Answers

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A JavaScript Developer is responsible for completing the design of applications and software using Javascript client-side programming language. JavaScript Developers work with websites, producing front-end applications and performing code analysis and overall improvement of style and usability.

Whether you're a job seeker preparing to be interviewed for the role of Javascript Developer or an employer preparing to interview candidates for Javascript Developer position, these Javascript Developer interview questions will help you prepare yourself for the job interview session.

Javascript Developer Interview Questions

Below are a list of some skill-based Javascript Developer interview questions.

1. Which javascript frameworks and technology stacks are you familiar with?
2. What are the advantages and disadvantages of using JavaScript?
3. Do you have any experience with MEAN?
4. What's your experience using JavaScript?
5. What other coding languages do you know?
6. How long have you been using JavaScript?
7. What‘s your experience with using server-side JavaScript?
8. How many years of experience do you have as a programmer?
9. What is the most recent coding language you learned?
10. Describe a time you fixed a particularly difficult error in a web application. How did you approach the problem? What debugging tools did you use? What did you learn from this experience?
11. Explain a time that you did a project using JavaScript that didn't work out. What happened?
12. Talk about your most recent successful JavaScript project.
13. How would you describe the relationship between javascript and html?
14. What's the difference between Java and Javascript?
15. Provide an example of when you would use a function in javascript.
16. How well do you understand the concept of scope in javascript?
17. Do you have experience working with asynchronous requests? How do you make asynchronous HTTP requests?
18. How is DOM utilized in JavaScript?
19. How are event handlers utilized in JavaScript?
20. What are break and continue statements?
21. When would you use a prototype in javascript?
22. Which keywords are used to handle exceptions in javascript?
23. How do you use the setTimeout function?
24. Describe differences between global scope and local scope.
25. What is the difference between an alert box and a confirmation box?
26. What are popular unit testing frameworks in JS?
27. Describe your approach to debugging javascript code.
28. What do you think is the most important skill for a javascript developer to have?
29. What is a RESTful Web Service?
30. How can the style/class of an element be changed in Javascript?
31. What is a Regular Expression?
32. How can you use JavaScript to check if a number is an integer?
33. Are you willing to learn new programming languages compatible with JavaScript to complete company goals?
34. Explain the five main types of data used in JavaScript and when to use each one.
35. What is the use of Void (0)?
36. Provide an example of when it would make sense to code a timer when programming with JavaScript.
37. What is the use of isNaN function?
38. What strategies do you use to provide consistent documentation when making updates to someone else’s original JavaScript code?
39. What steps would you take if you couldn’t figure out why the code you wrote wasn’t functioning properly?
40. Have you ever built a clicker counter from scratch before?
41. How can a page be forced to load another page in JavaScript?
42. What are all the types of Pop up boxes available in JavaScript?
43. What do you mean by NULL in Javascript?
44. How can you detect the operating system on the client machine?
45. What is the purpose of a deferred script and what is an example of the code you would use to implement them?
46. What is the use of Math object in JavaScript?
47. Explain “this” keyword
48. What kinds of errors do you see in JavaScript and how do you troubleshoot each one?
49. What would be the result of 3+2+"7"?
50. How can you change the background color of HTML document using JavaScript?
51. How can you submit a form using JavaScript by clicking a link?
52. What is the difference between == and === operators?
53. How does TypeOf operator work?
54. What is a cookie? Why do you need a cookie?
55. How do you parse JSON string?
56. Why do you need JSON?
57. How can you create, read and delete a cookie using JavaScript?
58. What is JSON and its common operations?
59. Write a count down timer program in javascript
60. Write a javascript program that generates random numbers
61. Write a javascript program that prints prime numbers from 1 to 100
62. Write a function that can determine whether a string is a palindrome

Javascript Developer Interview Questions and Answers

Every interview is different and the questions may vary. However, there are lots of general questions that get asked at every interview.

Below are some common questions you'd expect during Javascript Developer interviews. Click on each question to see how to answer them.

1. Why Do You Want To Leave Your Current Job?
2. What is Your Greatest Strength?
3. Tell Me About Yourself
4. Why Do You Want This Job?
5. Are You a Leader or a Follower?
6. What Is Your Greatest Accomplishment?
7. What is Your Salary Expectation?
8. Do You Have Any Questions for Us?
9. Why Should We Hire You?
10. What is Your Greatest Weakness?

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