Top 20 Web Developer Interview Questions & Answers

5.00 avg. rating (98% score) - 3 votes

Appearing for interviews can be intimidating and if you are underprepared, you can be overwhelmed and lose confidence in front of the interviewer. If you want to be successful in a web developer interview, you need to prepare for the commonly-asked questions. This article will provide some of the frequently-asked questions.

Web development is an important job profile in the age of internet and there are many big organisations which look to hire the best professionals. As a web developer, you should have good understanding and proficiency in all the popular web technologies like HTML5, CSS3 and JavaScript. There are various professional online courses in web development to gain those skills. Apart from that, one should also show good interpersonal and communication skills to stand out from the rest of the candidates.

The following web developer interview questions and answers will cover all the important areas:


Q1. What is a pseudo-class?


Ans. It is a CSS technique which sets the style when an element changes its state. E.g. style changes when mouse hover, different styles for visited or unvisited links, etc.


Q2. What is Namespacing in JavaScript?


Ans. It is usually not a good practice to use global variables in programming languages including JavaScript. However, you may be forced to use global variables sometimes. So, JavaScript introduces the concept of namespacing which ties down a part of the code and register it with a unique name.


Q3. How can you reduce page loading time?


Ans. These are the following ways you can reduce web page loading time: reduce image size, remove unnecessary widgets, HTTP compression, placing CSS at the top and script referencing at the bottom or external files, reduce lookups, minimise redirects and caching.


Q4. What is CORS?


Ans. Cross-Origin Resource Sharing (CORS) is a mechanism that enables different resources on a web page to be requested from another domain outside the domain from which the request originated.



Q5. What are the advantages of HTTP 2.0 over HTTP 1.1?


Ans. The major advantages are: headers compression, push notification, intelligent packet streaming management and parallel loading of page elements over a single TCP connection.


Q6. How do you take into account SEO, maintainability, UX, performance, and security when you’re building a web application?


Ans. Explain how you prioritise your actions as per the requirements of the organisation. If your organisation handles vital data, then security will be your top priority. If it is a medium-sized online business, SEO and UX might be your top priority and so on.


Q7. What are the new form elements introduced in HTML5?


Ans. The new form elements introduced in HTML5 are:

  • <datalist> – specifies a list of options for input controls.
  • <keygen> – generates an encryption key.
  • <output> – defines the result of an expression.


Also Read>>5 Latest Web Development Tools that you must know!


Q8. What’s the best way to integrate 5 different stylesheets into a website?


Ans. It usually depends on how the site is laid out. However, in most cases combining the stylesheets into single a one is the best approach. You can use Gulp to do so.


Q9. What’s the difference between Canvas and SVG?


Ans. Canvas is an HTML5 element which can draw graphics on the fly with the help of JavaScript. SVG (Scalable Vector Graphics) is used to display vector-based graphics on the web.


Q10. What is the default border size of a Canvas?


Ans. There is no default border size of a Canvas. You can adjust using CSS.


Also Read>>Create Your Own Mobile Application in 5 Simple Steps!


Q11. What is the difference between ID and Class selector?


Ans. ID selector finds and modifies the style to any single element while Class selector can do to any number of elements.


Q12. What is your preferred development environment?


Ans. This question is not about checking if you are perfect for the same environment as the organisation works but to measure if you are flexible to work in any environment. So, give them a hint that you are able to adapt to any environment with the core skills that you have.


Q13. Which are the new APIs provided by HTML5?


Ans. The new APIs are media API, text track API, application cache API, data transfer API, user interaction API, command API, constraint validation API and history API.


Q14. What are your key responsibilities in your current organisation?


Ans. Are you working in specific development areas? Do you only support the maintenance and upkeep of a website? Or Are you involved in all major steps in development including fixing bugs? Do not leave out any responsibilities which you think can help in leveraging your candidacy for the role.


Also Read>>Top Online Programming Courses


Q15. What is the difference between null value and undefined value?


Ans. Undefined means a variable has been declared but has not yet been assigned a value. On the other hand, null is an assignment value.


Q16. What are the web technologies that you are proficient in?


Ans. As already mentioned, you must have expert skills in three technologies: HTML5, CSS3 and JavaScript. Apart from that, you should be able to have at least some working knowledge of some of the other technologies like popular frameworks, APIs and database management.


Q17. What are the different types of pop-up boxes available in JavaScript? Explain them.


Ans. There are three types of pop-up boxes:

  1. Alert – it just displays a message with an OK button.
  2. Confirm – it pops up a confirmation message window with OK and Cancel button.
  3. Prompt – it pops up a dialog box asking user input followed confirmation buttons.


Q18. What is Scope in JavaScript? Name the different types of Scopes.


Ans. The scope defines the accessibility of the functions and variables in an application. There are two types of scopes: local and global.


Q19. What is the difference between ‘==’ and ‘===’ operators?


Ans. Though both of them belongs to the comparison operator category, the ‘==’ operator checks the value whereas, the ‘===’ operator checks both the value and the type.


Also Read>>How to Learn Android App Development?


Q20. By which mechanism in JavaScript can you detect the operating system on a client machine?


Ans. The operating system on a client system can be known by using the JavaScript property navigator.appVersion.

The above web developer interview questions and answers will help you to get an understanding of the type of questions you can expect in such interviews. However, if you need to gain expert-level skills to clear the technical round of interviews in any organisation, you should enrol in a certification course. Naukri Learning offers you a variety of online web development courses which you can enrol in and get certified to improve your chances of clearing an interview and getting a career boost.

About the Author

Hasibuddin Ahmed

Hasibuddin Ahmed

Hasib is a professional writer associated with He has written a number of articles related to technology, marketing, and career on various blogs and websites. As an amateur career guru, he often imparts nuggets of knowledge related to leadership and motivation. He is also an avid reader and passionate about the beautiful game of football.
Topics : Web Development