Front End Developer Interview Questions And Answers 2023

Last updated on Feb 06, 2023
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Front end Developer Interview Questions

In the world of technology, a developer should be passionate about coding and efficient enough to convert the client’s needs into the application. In the front end developer interview questions, this type of eagerness is something the interviewer is looking into the candidates.

As we all are aware that the topmost IT companies are looking to hire front-end developers who are responsible to create and manage responsive and interactive applications for all the devices by keeping simplicity and customer convenience in mind.

Generally, many of the developers got confused and worried about which type of front end interview questions, they might be asked for. Here we have listed a few common questions which are going to help you in your interview.

Skillset Expected from a Front end Developer

  • HTML and HTML5
  • JavaScript
  • JQuery
  • Ajax
  • CSS2 and CSS3 etc

Most Frequently Asked Front end Interview Questions

Here in this article, we will be listing frequently asked Front end Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q1. How would you optimize a website's assets resources?

Website’s assets resources are images, styles, scripts, and also external media.

To optimize these assets you can opt following ways-

  • Make all assets lightweight so that it's easy to download
  • The use of a Content Delivery Network (CDN) helps to optimize assets
  • While hosting assets on different domains make sure to reduce DNS lookups.
  • Use of CSS Sprites.
  • Disable etags.
Q2. What skills are required for front end developer?

Skillset required from a Front end Developer listed below:

Technical frontend developer skills

  • HTML and HTML5
  • JavaScript and JQuery
  • Responsive Design
  • Testing
  • Creativity
  • Version Control Systems and other developer tools
  • CSS3

Apart from the above mentioned technical skills also should have knowledge of cross browser testing, OOPS, CMS or any Framework and basic knowledge about SEO and tools.

Q3. What does CORS stand for and what issue does it address?

CORS is Cross-Origin Resource Sharing and it allows you to make requests from one website to another website. But for security reasons, a browser is not allowed to load requests to other domains when those requests are generated by scripts. CORS addresses this issue by supplying a header that will define which domains can make XMLHttpRequests.

Q4. What is the difference between local storage session storage and cookies?
Local Storage Session Storage Cookies
It stores data with no expiration date It stores data only for a session (until the tab is closed) These are text files that contain a small piece of data
The storage limit is maximum compared to two. The storage limit is larger than the cookie. The limit is less than 4KB for cookies.
The data stored in Local Storage can be easily read and change. The data stored in Session Storage can also be easily read and change. Data can only be read in the form of plain text.
Local Storage allows user to store Javascript primitives. Session Storage also allows you to store Javascript primitives. Cookies only allow you to store strings.
Q5. How do you improve website performance?
  • Minimize External HTTP Requests
  • Minify JS, CSS and HTML
  • Optimize JS and CSS Performance
  • Use CDN and Caching to increase Speed
  • Compress Images and Files
  • Prefetch should be Enable
Q6. What do you mean by Coffee Script and why it is used?

It is a small language that compiles into JavaScript. In this programs is written with less code and in more human readable forms.

The golden rule of CoffeeScript “It is just JavaScript”

  • It was developed by Jeremy Ashkenas in year 2009.
  • It is used because of CoffeeScript code is shorter and converts seamlessly to JS. It helps developer in writing an simple and easily readable code.
  • It is something which makes JS easier and effectively reducing our code to one third. It compiles into JS on execution which is Inspired by Python and Ruby.
Q7. What are three ways to reduce page load time?

There are many things responsible for reducing page load time. We will tell you the best three ways to reduce it’s loading time-

  • Image Optimization: Always scale your pics or videos before uploading them to a page.
  • Browser Cache: The use of cache will increase speed for pages that you have already visited.
  • Compress and Optimize Content: Compressing the content of a website reduces page load time to a great extent.
  • StyleSheet Reference on Top: Putting stylesheet reference to the header of a document helps your page to load faster
Q8. What is the difference between null and undefined?

It can be assigned to a variable and has no value in case of null but on the other hand undefined means a variable has been declared but has not yet been assigned a value.

Q9. How to get length of number in javascript?

var x = 840;

Q10. What is callback function in Javascript?

A callback function is a function which is accessible by another function and invoked after the first function if that first function completed.


    $("p.button").hide("slow", function(){
        alert("Front end Interview Questions and Answers");

That’s it, hope you will find these front end engineer interview questions helpful. Though we are sure that these questions and answers are going to assist you in your interview since this list has been prepared by our experts. If you think we have missed out on anything important, please feel free to share your inputs in the comment section.

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