Interview Questions For Front-End Developers

A front-end developer is always in demand to build websites and give a hassle-free experience to the clients. For a front end developer, interview questions can be challenging and inquisitive as amateur developers usually find it crafty to explain their workflow.

The interview process for a frontend developer is a highly tricky and thorough process that involves certain phases and unlike other tech interviews, the focus is primarily given to the candidate's practical work experience and skills.

Due to the rigorousness and thoroughness of the entire process, potential developers need to not just have the depth and clarity in their fundamental knowledge, but also have live work portfolios and links to their projects so that the potential employer may get an impression of their skills.

The Front-end developer interview questions are mainly classified into two rounds-0ne being technical, and the other one is specifically related to the practical knowledge and application of the desired skills.

The technical part will include the fundamental questions of your domain including the knowledge of the candidate regarding processors, their various types, and how every one of them works. In this article, we will be sharing a few common frontend questions asked in an interview. A potential candidate is expected to be familiar with the various mechanisms involved in frontend web development, including, cross-origin resource sharing, frontend optimization, Get and Post requests, etc. Familiarity with not just the processes, but how they work and affect the software is mandatory.

An interviewer might also inquire about the various languages that you’re familiar with and their application and usage. A frontend web developer doesn’t just have to rely on the knowledge, but the technical and practical aspects of it as well.

Some of the commonly asked technical questions for a frontend web developer interview are:

Q1. What skills make a complete front-end developer? Or what are the crucial skills needed for a front-end developer?

The crucial skill need for a front-end developer are as follow

  • HyperText Markup Language (HTML)

  • CSS

  • JavaScript

  • JQuery

  • Version Control

  • Testing and debugging skills

Apart from these, some more additional skills can enhance the profile. The most obvious is the ability to build a user-friendly responsive design for a good website where the users surf smoothly. Possessing soft skills like creativity and efficient communication skills can amplify your chances of being selected for the job. Additionally, having proficiency in Content management systems like WordPress, Joomla, and Drupal can be impressive. Knowledge of SEO will give you a niche amongst the other candidates.

Q2. Explain the layers present in a webpage. How CSS plays its role in it?

There are 3 kinds of layers on any web page. These are

  • Content/ Structure Layer

  • Presentation Layer

  • Behavior Layer

The content layer is the information that a website holds. It comprises the text and graphics which the visitor on the website observes. Next, as the word suggests, the Presentation layer defines how the content on the website will be presented to the visitors. Lastly, the behavior layer establishes the website's reactions to the user's command.

CSS is primarily used for the presentation layer. It enhances the design of certain elements present on the webpage. Cascading Style Sheets contain stylistic instructions that magnify the visual appeal of the webpage.

Q3. Tell me something about W3C.

W3C stands for World Wide Web Consortium which is an international standard for the web. W3C is responsible for standardizing the web and making it accessible to all users. It recommends web protocols and procures standards for CSS, CGI, EME, HTML, and many more.

Q4. As a developer what ways are applied to reduce the load time of any given website?

Websites might be lagging load time because of several reasons like server load time, or the number of redirects to name a few. As a developer a few ways to reduce the load time of a given website could be done as follows:

  • Enable a proper browser caching

It is a significant step to reduce the load time for a first-time user on the webpage. It will allow you to store the cached version of the images HTML document, javascript files, etc. in the user's browser which in turn will increase the load time.

  • Optimize the image files

Large image files delay the process of loading. Cropping the images is a useful mechanism instead of resizing it. JPG format of images would be more preferable as compared to PNG or GIFS. Compressing is yet another option to reduce the load time.

  • Minimize the HTTP requests

If there are more components on the page, it will take a longer time for the web page to load. Hence, a developer can minimize the components like pictures, scripts, and stylesheets.

  • Reduce redirects

Redirecting creates unnecessary requests and adds to the loading time. Avoiding the usage of 301 directs can help.

Q5. What are the components of a CSS style?

The CSS style is made up of three things

1. Selector: A selector is an HTML tag where styles can be applied. A selector tag can be anything of <h1> or <table>

2. Property: This is an attribute of the HTML tag. This property can be anything like colors, borders, shades, etc. The HTML attributes are converted into CSS property.

3. Value: A value is always assigned to any defined properties.

Q6. What is Content Security Policy?

Content Security Policy (CSP) detects attacks used for data theft or malware distribution and curtails them. An HTTP header is added to a webpage which restricts the user agent to load resources for the given page. It is a shield against cross-site scripting attacks (XSS).

Q7. What is encapsulation?

Encapsulation is a crucial component of Object-Oriented Programming (OOP) which pertains to bundling the data with the methods that operate on it. It is also utilized for the process of information hiding i.e to hide internal representation or an object from outside.

Q8. What is the difference between HTML and XHTML?

HTML is the HyperText Markup Language which is used to develop and link web pages. It has a document file format. XHTML is the abbreviation of Extensible Hypertext Markup Language. It has features of both XML and HTML. It has markup format language. Moreover, in HTML the tags and attributes could be in both the lower and uppercase but in XHTML, it necessarily has to be in lowercase.

Q9. What are the benefits of Coffee Script over Javascript?

CoffeeScript is a programming language transpiled with Javascript. However, it has smaller and readable codes as compared to JavaScript. The Javascript code is complicated as compared to Coffeescript. The function and whitespaces are easy to map in Coffeescript. The everyday task gets simpler to perform with Coffeescript.

Q 10. What is the Thread-Local object in Python Task?

Thread- Local objects are used to keep the tasks simpler and avoid too many codes. It is designed to store in a distinct structure and tie it to the current thread. It has a request context to choose to view represented by 'g' and 'request' objects. However, it requires a valid request context if you are trying to view it without an incoming request.

Apart from this, preparing for on spot practical tasks like recreating layouts in HTML or CSS on a particular platform ( ask the format before you go for the interview) is a must as such tasks are common in front-end interviews.

While answering the questions, be careful to interact with the interviewer. First, understand the problem and then start writing the code. Furthermore, the frontend developer can showcase their projects and work experience to discuss them with the interviewer.

Questions such as, “How do you structure your CSS and JavaScript to make it easier for other developers to work with?” or “ What are your favorite types of front end development projects to work on? What do you like about them?” will give the employer an idea about the practical tech knowledge.

Keep calm and give interviews!!