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Front End Interview Questions With Answers

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How Do You Stay Up

Frontend Interview Questions 2021 | Front End Developer Interview Questions And Answers |Simplilearn

The aim of this question is to determine whether the candidate has current knowledge of the industry. Here’s what to look for in an answer:

  • understanding of recent industry news and trends

  • a proactive approach

  • willingness to update their knowledge consistently

Example:âI keep updated with industry trends, news, and techniques by reading industry magazines. Some of my favourite web design magazines are Creatively Blocked and Smushing Magazine. I also enjoy various magazines about the web development process. I read an article or two a day with my breakfast to stay up-to-date.â

Define The Anonymous Function In Js

Generally, the function name is defined when we define the function itself, in normal user-defined functions, but in the case of an anonymous function, the function name is not defined. Here we make use of an assignment operator and variable to stow the function as an object, then utilizing that variable, we will be capable to invoke the function itself.


What Coding Languages Do You Have Experience With

The aim of this question is to assess the candidate’s technical knowledge of different programming languages. Here’s what to look for in an answer:

  • experience working with different coding languages

  • ability to use the coding language you prefer

  • knowledge of various coding languages

Example:âIn my previous role, I used HTML, JavaScript, Coffee Script, CSS, SQL, and PHP. I prefer Coffee Script over JavaScript, so that’s where most of my experience lies, but I’m also proficient with HTML and CSS. I’m always willing to learn new coding languages to further develop my knowledge.â

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What Is Functional Programming In Javascript

In JavaScript, functional programming is a programming paradigm mainly designed to handle pure mathematical functions as it focuses on writing more compounded and pure functions. It is used in JavaScript as JavaScript is a multi-paradigm language. In JavaScript, we can easily mix a lot of different paradigms inside a simple piece of JavaScript code. We can use procedural, object-oriented, and functional programming paradigms simultaneously in JavaScript, which makes it more powerful.

What Are Meta Tags

Top 10 front end clerk interview questions and answers

The aim of this question is to test the candidate’s technical knowledge. What to look for in an answer:

  • Understanding of meta tags
  • In-depth industry knowledge


“Meta tags within an HTML document give information about the webpage. Meta tags don’t appear on the website but search engines and browsers use them to help people find the website or navigate the webpage. Meta tags typically consist of data about the document’s title, author, description, keywords, or character set.”

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What Is Content Security Policy

Content Security Policy is an HTTP header that allows operators to monitor and control where resources can be loaded onto their website. Using this header is one of the best ways to prevent cross-site scripting vulnerabilities. Since there are difficulties with retrofitting CSPs on all existing websites, CSP is a must for all new websites, and it is highly recommended to implement CSPs on all existing high-risk sites.

The biggest benefit of CSP is disabling the use of unsafe-inline JavaScript. Inline JavaScript means that data that users enter incorrectly on the site can generate code that will be interpreted by the browser like JavaScript. By using CSP to disable inline JavaScript, you can effectively eliminate almost all XSS attacks against your site.

In An Image Tag What Is The Benefit Of The Srcset Attribute

srcset is utilized when we wish to generate several resolutions of the exact image on several devices. This improves the UI. The browser will display low resolution on low-end devices, and high resolution of an image on high-end devices.


< img srcset="picture_low.jpg 480w,             picture_high.jpg 800w"     sizes=" 480px,            800px"     src="picture_high.jpg"     alt="Elva dressed as a fairy"> 

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How Do You Ensure The Websites You Design Promote Accessibility And User

The aim of this question is to assess the candidate’s experience and knowledge of creating accessible, user-friendly websites. Here’s what to look for in an answer:

  • ability to create user-friendly, accessible websites

  • specific ways the candidate promotes accessibility

  • experience in a front-end development role

Example:âCreating websites that are user-friendly and accessible is extremely important to me, as I want everyone to enjoy my work. If the client agrees to it, I add alt text to images so screen readers can describe the picture to those with visual impairments. Similarly, I can create websites that allow users to enlarge or minimize the font to make it easier to read. I test my web applications on various browsers and devices to check how easy they are to use.â

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What Are The Basic Skills Set Required To Be A Front

Front End Developer Interview Questions with Answer Examples

The basic skillset for a front end developer includes but is not limited to the following:

  • HTML
  • Knowledge of Content Management Systems Like WordPress, Drupal, OpenCart, Joomla, & Shopify
  • Well aware of PHP functions & Features
  • JQuery
  • Debugging & testing procedures at cross-browser
  • Understanding of Adobe Illustrator & Photoshop
  • Some basic know-how of SEO tools and techniques

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Suggest How Can We Optimize Our Front

  • The consumption of resources can be reduced by the pages by enhancing the server response.
  • Utilize JavaScript and External CSS instead of internal or in-line.
  • Utilize the framework to ensure the front-end becomes more responsive to different devices.
  • Open-source libraries can be used to manage the browser-specific styling issue.
  • Make use of progressive loading like Lazy Loading to enhance the rendering of heavy elements, like videos and images.
  • Connect the style sheet in the header and script at the top of the HTML’s body tag.
  • Utilize browser storage to keep user-specific private data.

Q2 How Does The This Keyword Work In Javascript

In JavaScript, âthisâ is set to the window object. Its value depends on whether or not you are in strict mode. A strict mode âthisâ will be undefined in a top-level function, while a non-strict mode âthisâ will be the window object. The value of âthisâ can be overwritten with the bind method.

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What Is A Higher Order And Pure Components In React

Higher Order Components

  • A higher-order component is a function that takes a component and returns a new component.
  • It facilitates reusing of component logic.

const NewComponent = higherOrderComponent

Pure Components

  • React.Component is the base class for React components. React.PureComponent is a variation of React.Component class and does a shallow comparison of props and state.
  • A React component can be considered pure if it renders the same output for the same state and props.

How Do You Ensure Your Code Is Easy For Other Developers To Understand

6 most popular front

The aim of this question is to assess the candidate’s skills and ability to work as a team. What to look for in an answer:

  • Willingness to work as a team
  • Understanding of their role
  • Ability to create clean, easy-to-understand code


“I make all of my code as simple and organised as possible to make it easy for my colleagues to follow. I also use comments throughout the code to make it easier to change. I avoid deep nesting when possible and group my code to limit line length and disorganisation. I also create a style sheet for every project for my team to follow along with. Ensuring my code is easy to understand makes working as a team much easier.”

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Can You Explain The Concept Of A Css Float And Provide An Example Of Its Usage

Answer: This answer will require some memorization and a bit of confidence!

The average bootcamp grad spent less than six months in career transition, from starting a bootcamp to finding their first job.

  • A concrete definition of CSS floats
  • Examples of how you use this element in your code
  • Confidence in explaining this technical concept to any audience

Take Along Samples Of Your Work

If you have a portfolio, take your laptop or tablet in with you to show the employer samples of your work. This will allow you to explain your work in greater detail, including showing off your code under the hood. This interaction with your work will create a more memorable impression than just giving a description or a link.

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What Is Aot Compilation How Is It Different From Jit

Ahead of Time , compilation translates your code as it is being built, rather than when it is downloaded and run by the browser. This guarantees that the browser renders content quickly. Include the aot option with the ng build or ng serve commands to specify AOT compilation.

The Just-in-Time compilation technique converts computer code to machine code while it is being executed or run. Dynamic compilation is another name for it. When you use the ng build or ng serve CLI commands, by default it uses JIT compilation.

What Is The Difference Between Attribute And Property

Frontend Interview Experience (Unacademy) – Javascript and React JS Interview Questions

Attributes are an element of an HTML document while properties are a part of the Document Object Model .

Example: < input type=”text” value=”Tech”>

Here, value and type are the attributes of HTML, but when the statement is read by the browser and parses this code it will make a DOM with different properties, like accept, autofocus, accessKey, baseURI, checked, childElementCount, align, alt, childNodes, children, classList, className, attributes, and clientHeight.


var data = document.querySelector   // here we created a document object of input tagconsole.log)  // tech  // getting the attribute valueconsole.log  // tech   // getting the property of the input object

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Why Should We Hire You As Frontend Developer

  • Freshers: While interviewing for front-end developer jobs for freshers you can come across this question. The best answer would be, ” I have just begun my career, and do not have practical achievements, but I wish to explore and experience my potential by giving the best services to the company. It will be my privilege to work with your organization.”
  • Experienced: The best answer would be, You should hire me for the role of front-end developer owing to my proven ability to create effective front-end user interfaces in line with contemporary best practices. I have experience working with JavaScript, along with the React framework, to create front-end applications.

Has A Client Or Team Member Ever Been Unhappy With Your Work What Happened

The aim of this question is to assess the candidate’s ability to handle conflict professionally while still maintaining relationships. What to look for in an answer:

  • Ability to resolve conflict
  • Strong interpersonal and communication skills
  • Experience working with clients and team members


“A colleague was unhappy with the font I used on one of my websites as it didn’t match the client’s notes. I missed the note about the font type the client wanted and changed it immediately. I was glad my colleague caught the error before we submitted the website to the client. I now double check every clients’ notes before submitting any work.”

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What Do You Think A Front

The aim of this question is to assess the candidate’s understanding of the role and ability to work well within a team. Here’s what to look for in an answer:

  • understanding of the role

  • willingness to work collaboratively

  • strong industry knowledge

Example:âFront-end developers work closely with back-end developers to create a visually appealing, cohesive website. They ensure a website looks good and functions properly by utilizing their team’s code. Developers have an in-depth understanding of coding languages and design aspects to create a well-balanced website.â

Can You Explain What User

2021 Front End Developer Interview Questions (And Answers!)

The aim of this question is to assess the candidate’s technical knowledge. What to look for in an answer:

  • Understanding of user-centred design
  • Ability to name the benefits of user-centred design
  • Willingness to implement user-centred design in their work


“User-centred design is a process that web developers use to focus on the client’s needs, requirements, and customer base. Through every aspect of the design process, the front end developer will focus on what the user of that website needs. User-centred design requires a lot of research to work but is very beneficial. It often creates a more successful website with more organic traffic as the developer makes it with the user in mind.”

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What Is A Sql Injection

Another type of attack. If you have a search form, for example, and when a user types in a name like “Kelly” you take that string and do an SQL lookup for it. Let’s say your SQL looks like this:

`SELECT * FROM Users WHERE UserId = yourVariable`

An attacker could put something malicious in the search bar like `Kelly OR 1=1`, and now it will return a list of all users instead of just the requested one.

Back End Developer Skill Set

The back end developer hiring test is important for hiring server-side programmers. Before going into the backend interview questions and answers, we need to first examine what employers should look out for in a backend developer candidate? These factors may be helpful, even if this list is by no means exhaustive.

  • A company may not request a computer science degree. Although, this is no longer necessary in a number of places as long as a candidate demonstrates an understanding of computer science concepts such as algorithms, coding theory, and computer networking.
  • Proficiency in cloud computing services such as Amazon Web Services, Microsoft Azure, Google Cloud, etc.
  • Fully understand and be competent to work with database technologies such as MySQL, Microsoft SQL Server, Oracle, MongoDB, etc.
  • Soft skills such as teamwork, critical thinking, and innovation.
  • For senior developers, leadership skills are important

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Mention The Difference Between Mysql And Mongodb

  • MySQL: It is a Relational Database Management System , which makes use of SQL as a standard language to handle its database. Like different relational database management systems, MySQL makes use of a table-like structure to stow data.
  • MongoDB: MongoDB is a NoSQL database that utilizes the JSON-like structure to stow data elements. To modify and access data in MongoDB, the programmer ought to make use of the MongoDB Query Language .

Skillset Expected From A Front End Developer

Frontend Interview Experience (Cars24) – Javascript and React JS Interview Questions
  • HTML and HTML5


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.


There are many things responsible for reducing page load time. We will tell you the best three ways to reduce its 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


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.


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Q3 How Can We Ensure A Web Design Is User

As a Front-end developer, visualizing the design for the app closely with the user experience team, testing the web app, taking user feedback, and ensuring the app runs smoothly on different platforms and phones will help create a user-friendly web design.

Learn more about the roles and responsibilities of a Front-end Engineer here.

More Sample Front End Developer Interview Questions For Practice

Here are a few more front-end developer interview questions on JS, CSS, HTML, and web design for your practice:

  • What are the pros and cons of extending built-in JavaScript objects?
  • What are the benefits of using spread syntax, and how is it different from the rest of syntax?
  • Give an example for destructuring an object or an array.
  • What are the ways to integrate CSS into an HTML page?
  • How would you fix browser-specific styling issues?
  • What do you know about styling SVG?
  • What is the use of the Clearfix CSS property?
  • What is progressive rendering?
  • Explain the difference between layout, compositing, and painting.
  • What are the differences between Long-Polling, Server-Sent Events, and Websockets?
  • What are the best tools to find a performance bug in your code?
  • How can you test JavaScript code?
  • This completes the list of important front end developer interview questions and answers. In addition to these, you must also practice some coding problems to ace your front end interview.

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    What Is View Encapsulation In Angular

    View encapsulation defines whether the template and styles defined within the component can affect the whole application or vice versa. Angular provides three encapsulation strategies:

  • Emulated – styles from the main HTML propagate to the component.
  • Native – styles from the main HTML do not propagate to the component.
  • None – styles from the component propagate back to the main HTML and therefore are visible to all components on the page.
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