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Frontend Developer Interview Questions and Answers [Top 100]

Frontend development is a hot field with companies actively seeking skilled developers, offering attractive salary packages. If you’re keen on pursuing a career as a frontend developer and feel you’ve got the necessary skills, you’re on the right track. This guide to Frontend Developer Interview Questions is tailor-made to assist you in acing your upcoming interview. It compiles a range of questions covering different languages and frameworks crucial for frontend development.


Front End Developer Interview Questions for Freshers

  1. What do meta tags signify in HTML?

    Meta tags reside within the HTML Head tag and are pivotal for browsers, not the interface. They typically comprise name-value pairs and include elements like character encoding, title, and description.

  2. Name a few fundamental design elements.

    Basic design components include Line (a mark created by various tools), Size (the space occupied by a shape), Texture (the surface quality like smoothness or gloss), and Color (defined by hue, value, and intensity of light reflected).

  3. Define load balancing.

    Load balancing involves distributing incoming network traffic across multiple backend servers.

  4. Expand on the abbreviation ‘npm’.

    Npm stands for Node Package Manager, serving as a vital tool for managing packages in the Node.js ecosystem.

  5. Explain the concept of scope in JavaScript.

    In JavaScript, each function operates within its scope, defining rules for variable access and management within its domain.

  6. Distinguish between JavaScript and jQuery.

    JavaScript is the core language, while jQuery is a JavaScript library designed to simplify DOM manipulation and event handling.

  7. What is Content Security Policy (CSP)?

    CSP, an HTML header, empowers site operators with control over resources loaded on a webpage, enhancing security by preventing certain types of attacks like Cross-Site Scripting.

  8. Elaborate on Cross-Site Scripting (XSS).

    XSS occurs when attackers inject malicious scripts into web applications, leading to the execution of unauthorized actions by unsuspecting users.

  9. Define User-Centered Design.

    User-Centered Design focuses on creating designs that cater to user needs, involving users in every stage of the design process.

  10. Explain ‘callback hell’.

    Callback hell refers to complex JavaScript code structured in a pyramid-like fashion due to nested callbacks, making code difficult to follow and manage.

  11. Define Polymorphism.

    In object-oriented programming, polymorphism denotes the capability of a single interface to support multiple functionalities.

  12. What is Strict Mode in JavaScript?

    Strict mode in ECMAScript 5 enforces a more secure and optimized context for coding, identifying and preventing common coding errors.

  13. What does the KISS principle entail?

    The KISS principle, or “Keep it simple, stupid,” emphasizes that simpler systems function more effectively, originally coined as a design strategy in the US Navy.

  14. Unpack the meaning of SOLID in object-oriented design.

    SOLID encapsulates key principles: Single Responsibility, Open-Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion.

  15. Explain ClickJacking.

    ClickJacking involves tricking users into interacting with one element while unknowingly interacting with another, often a malicious entity.

  16. Define Coercion in JavaScript.

    Coercion refers to the conversion of different JavaScript data types, occurring either explicitly or implicitly.

  17. What are IIFEs?

    Immediately-Invoked Function Expressions (IIFEs) are functions that execute immediately after their creation, maintaining encapsulation and avoiding global scope pollution.

  18. Describe the CSS grid system.

    The grid system in CSS offers a structured layout for content placement, facilitating consistent organization using rows and columns.

  19. Methods to reduce page load time.

    Optimizing images, utilizing browser caching, and compressing or optimizing content are effective techniques to decrease page load times.



Front End Developer Interview Questions for Experienced


  1. What is Stringify in JavaScript?

    Stringify is a method in JavaScript used to convert a JavaScript object into a string representation, facilitating easier data transmission or storage.

  2. Identify the components of the CSS Box Model.

    The CSS Box Model encompasses four primary constituents:

    • Content: Represents the actual content area within an element.
    • Padding: Space between the content and the border.
    • Border: The visible boundary surrounding the padding and content.
    • Margin: The external space outside the border, providing separation from other elements.
  3. What is the advantage of using Srcset?

    Srcset is employed to generate various image solutions suited for different devices, enhancing user interface and responsiveness by allowing the browser to select the most appropriate image size based on the device’s specifications.

  4. What is MySQL?

    MySQL serves as a relational Database Management System, utilizing SQL as its primary language for database management. Similar to other databases, MySQL organizes data in a table-based structure.

  5. Define MongoDB.

    MongoDB is a NoSQL database that represents data elements using a JSON-like structure. Alterations in MongoDB require the use of the MongoDB Query Language, offering flexibility in data storage and retrieval.


HTML Interview Questions

HTML forms the backbone of Frontend Development, and these interview questions focus on key aspects of HTML.

  1. What Is an Attribute in HTML?

    Attributes are properties added to HTML tags, altering their behavior or display. They are placed within the tag brackets, immediately following the tag name. For instance, in <h1>Hello</h1>, the <h1> tag represents an attribute.

  2. What is Marquee in HTML?

    Marquee is utilized to scroll text or images on a webpage, moving content automatically in various directions. It’s applied using the <marquee> tags.

  3. What is Semantic HTML? How does it work?

    Semantic HTML employs markup to emphasize the content’s meaning. Instead of using <b> for bold or <i> for italic, semantic HTML utilizes <em> and <strong> to represent emphasis and importance in content.

  4. How do you Display a Table on an HTML Webpage?

    Tables in HTML are structured using <table>, <tr> for rows, <td> for data cells, and <th> for headers.

  5. What is SVG in HTML?

    HTML SVG represents vector and raster graphics described in XML text files. It’s commonly used for diagrams and graphical representations such as pie charts and 2D graphs.

  6. In HTML, how do you separate a section of text?

    HTML provides various tags to segment text:

    • <br> tag: Breaks a line of text.
    • <p> tag: Creates a text paragraph.
    • <blockquote> tag: Indicates quoted passages.
  7. How do you Create Nested Web Pages in HTML?

    By using the <iframe> tag, you can embed one webpage within another, creating a nested web page.

  8. Differentiate Between Ordered List and Unordered List


    • Unordered lists use <ul> tags with each list element marked between <li> tags.
    • Ordered lists use <ol> tags and include list elements between <li> tags, with a specified numerical or alphabetical order.

Now, let’s explore the next series of interview questions, focusing on CSS.


CSS Interview Insights

  1. What’s the preferred way to apply CSS in HTML?

    Incorporating CSS in HTML can be approached in three ways:

    • Inline CSS: Best for individual element styling or minimal styling requirements.
    • External Style Sheet: Ideal for styling numerous elements or multiple HTML pages.
    • Internal Style Sheet: Suitable when a single HTML document requires a distinct style across multiple elements.
  2. Enumerate CSS Selector Types

    • Universal Selector
    • Element Type Selector
    • ID Selector
    • Class Selector
    • Descendant Combinator
    • Child Combinator
    • General Sibling Combinator
    • Attribute Selector
  3. What’s Sass, Less, and Stylus?

    • Sass: Abbreviation for “Syntactically Awesome Style Sheets”, often denoted with a $ sign for variable declaration.
    • Less: Acronym for “Leaner Stylesheets”, defined with the @ symbol for variables.
    • Stylus: Known for its flexible syntax without the need for symbols like @ or $ for variable declaration.
  4. Explain the Box Sizing Property

    The Box Sizing property governs the calculation of a box’s height and width, utilizing three key models:

    • Content Box
    • Padding Box
    • Border Box
  5. Different Methods to Hide an Element in CSS

    • display: none: Conceals content and doesn’t retain it in the Document Object Model (DOM).
    • visibility: hidden: Element is present in the DOM, occupying space, but remains invisible.
    • position: absolute: Allows elements to be positioned off-screen.
  6. Which Property Handles Text Underlining, Strikethrough, and Overlining?

    The property responsible for underlining, strikethrough, and overlining text is text-decoration.

I’ve condensed and restructured the information to ensure clarity and coherence for those delving into CSS concepts.


JavaScript Interview Insights

  1. What is JavaScript and its Key Features?

    • JavaScript is a high-level, interpreted programming language primarily used for web development.
    • It’s versatile, supporting both object-oriented and functional programming paradigms.
    • Offers dynamic typing, making it flexible for various data types.
    • Known for its event-driven, asynchronous nature, crucial for creating responsive web applications.
  2. What are the Different Data Types in JavaScript?

    • Primitive Types: Includes numbers, strings, booleans, null, undefined, symbols (ES6), and BigInt (ES11).
    • Reference Types: Objects (including arrays and functions) are reference types.
  3. Explain Asynchronous JavaScript and Event Loop

    • Asynchronous JavaScript allows non-blocking execution, enabling multiple operations to occur without waiting for each other to complete.
    • The event loop manages the execution of asynchronous operations, ensuring efficient and ordered processing of events and callbacks.
  4. What are Closures in JavaScript?

    • Closures are a key concept in JavaScript, referring to the ability of a function to remember and access its lexical scope even when executed outside that scope.
    • They enable powerful programming patterns, facilitating private variables, encapsulation, and callbacks.
  5. Differentiate between ‘let’, ‘const’, and ‘var’

    • ‘let’ and ‘const’ were introduced in ES6 while ‘var’ has been in JavaScript since its early versions.
    • ‘let’ allows variable reassignment but restricts redeclaration within the same scope. It’s block-scoped.
    • ‘const’ creates variables that can’t be reassigned and must be initialized during declaration. It’s also block-scoped.
    • ‘var’ is function-scoped and allows both redeclaration and reassignment.
  6. What are Promises in JavaScript?

    • Promises are objects representing the eventual completion or failure of an asynchronous operation.
    • They help manage asynchronous operations, offering a cleaner alternative to callbacks, simplifying error handling and chaining multiple async calls.
  7. Explain ES6 Features and their Advantages

    • ES6 (ECMAScript 2015) brought significant enhancements to JavaScript, introducing features like arrow functions, template literals, const and let declarations, classes, destructuring assignments, and more.
    • These features enhance code readability, efficiency, and enable the use of modern programming patterns.