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.

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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.

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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.

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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.

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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.

Q21. Which one do you use the most, CSS Animations or JavaScript Animations?

Ans. Both. CSS animation and JavaScript animation are the two primary ways of creating web animations. As per the project requirement and the kind of the desired effect, I have used both of them.

Cases when CSS animations work well:

  • When the transitions are simple. For example, toggling within the element states.
  • When the UI elements are self-contained. Like in showing a tooltip.

Cases when JavaScript animations work well:

  • When advanced animation effects are expected in the project, like bouncing, stop pause, etc.
  • When a superior level of control is required, JS animation works well.
  • Helpful when drawing in HTML canvas.

Q22. Have you used Git for pushing live changes on the website?

Ans. Yes, Git is a great help to streamline live updates on the website. For this, I made use of a post-receive hook. Through this, I was able to copy updates from remote server repo and update it onto the live site.

Q23. Which web development tools do you use?

Ans. There are several web development tools available and being into the role of a web developer, I have used multiple of them like:

  • GitHub to work together with a team on a particular project.
  • CodeKit to minify, combine, and syntax-check in JavaScript.
  • JS to structure the web application and even develop a one-page application.
  • CodePen to deploy a website and build test cases.
  • Grunt for automating repetitive tasks.

Q24. As a web developer, how do you optimise your site’s loading time?

Ans. As a developer, I will optimize the site by –

  • Implementing caching
  • Minifying CSS, HTML, and JavaScript codes

Q25. How is HTML different from XHTML?

Ans. HTML and XHTML are both known for writing web pages. But, HTML is extended from SGML tagging whereas XHTML is an application of Extensible Markup Language (XML).

 HTML has three components – element tag pair (start tag and end tag), attributes of the element within the tag, and content in the form of both text and graphics. Whereas XHTML includes only a single root element which includes lower case elements and the value that is assigned should be closed, nested, and must be surrounded by quotation marks. Looking at the difference, XHTML is more expressive when compared to HTML.

Q26. Have you gone through our website? Please mention what you didn’t like about the site?

Ans. Now, this is a tricky question and here the interviewer is checking your skills to identify what is good as per you and as a developer how in-depth knowledge do you have about the site’s functionality. So, the first thing is that you must visit their website before appearing for the interview as this will show your interviewer that you are serious about the role and at the same time you are well-prepared. Next, you need to do is observe some good points about the site from a developer’s point of view and also make a checklist of pitfalls. Note, please mention only genuine points where your expertise can be of help.

Q27. How do you handle a client who is unhappy with your team’s web delivery?

Ans. For every company, the client is the king and no one wants to lose his or her clients at any cost. Therefore, when appearing for a web developer interview round, you must be well prepared as the recruiter can shoot this question. You can start by narrating any previous incident that is related to client handling. Define the issues the client was facing, and later narrate the solutions, which you or your team had performed to help the client. This will let the recruiter know that you have the capability to handle and nurture clients.

Q28. What do you know about HTTP/3?

Ans. HTTP/3 is the new third-generation HTTP standard that was recently made available in late 2019. It is known for its new standards, fast, reliable, and secure connection. HTTP/3 promises faster web experience as it uses QUIC. This new internet transport protocol introduces first-class citizens. Brands like Google and Facebook are now using QUIC because of its swift abilities to speed up the web.

Q29. What will you do when an image or a hyperlink is not displaying correctly?

Ans. Many times it happens that some images are not properly displayed on the page and that severely affects the SEO and if happens multiple times, it hampers the overall rankings. So, I keep on checking things like missing href and alt tags.

Q30. Do you have any experience in developing multilingual websites?

Ans. It is not necessary that you hold experience in developing multilingual sites but you must know the basics of how it is done. You can tell the recruiter the process that involves Unicode encoding and usage of the ‘lang’ attribute.