100+ Front end Developer Interview Questions and Answers for Freshers

Flexbox is a CSS layout model that allows for responsive design by distributing space along a single axis.

• Flexbox stands for 'Flexible Box' and is designed for one-dimensional layouts.

• It uses properties like 'display: flex;' to create a flex container.

• Items within the container can be aligned and distributed using properties like 'justify-content' and 'align-items'.

• Example: 'justify-content: center;' centers items horizontally.

• Flexbox allows for flexible item sizes, adapting ...read more

Yes, span is a tag in HTML used to apply styles to inline elements.

• Span is an inline element used to apply styles to a specific section of text or content.

• It does not add any extra space or line breaks.

• Example: <span style='color: red;'>This text will be red</span>

World Wide Web

• Stands for World Wide Web

• A system of interlinked hypertext documents accessed via the Internet

• Commonly used to browse websites and access information

Props are used to pass data to components, while hooks manage state and lifecycle in functional components.

• Props are immutable and passed from parent to child components.

• Example: <ChildComponent name='John' /> - 'name' is a prop.

• Hooks, like useState and useEffect, allow functional components to manage state and side effects.

• Example: const [count, setCount] = useState(0); - 'count' is state managed by a hook.

• Props are used for data flow, while hooks enable stateful logic in fu...read more

React's lifecycle consists of phases that manage component creation, updating, and unmounting for efficient rendering.

• Mounting: Components are created and inserted into the DOM. Example: constructor() and render() methods.

• Updating: Components re-render in response to state or props changes. Example: componentDidUpdate() lifecycle method.

• Unmounting: Components are removed from the DOM. Example: componentWillUnmount() for cleanup tasks.

• Hooks: React 16.8 introduced hooks like us...read more

Functions are reusable blocks of code, while components are self-contained UI elements in frameworks like React.

• Functions are defined using the 'function' keyword or arrow syntax, e.g., 'const add = (a, b) => a + b;'.

• Components are typically defined as classes or functions in frameworks like React, e.g., 'const MyComponent = () => <div>Hello</div>;'.

• Functions can return values or perform actions, while components return JSX or HTML to render UI.

• Components can manage their own...read more

Create and center three boxes on the screen using HTML and CSS.

• Use HTML to create three div elements for the boxes.

• Apply CSS to style the boxes with width, height, and background color.

• Use Flexbox or CSS Grid to center the boxes on the screen.

• Example CSS: .container { display: flex; justify-content: center; align-items: center; height: 100vh; }

• Example HTML: <div class='box'></div> for each box.

Creating a responsive layout involves using flexible grids, media queries, and fluid images to adapt to various screen sizes.

• Use a fluid grid system with percentages instead of fixed units. For example, set a container width to 100% and child elements to 50%.

• Implement media queries to adjust styles based on screen size. For instance, use '@media (max-width: 600px) { ... }' to change layout for mobile.

• Utilize flexible images by setting max-width to 100% to ensure they scale wi...read more

Padding is the space inside an element, while spacing is the space around an element.

• Padding is the space inside an element, between the content and the border.

• Spacing refers to the space around an element, including margins and borders.

• Padding can be adjusted using CSS properties like padding-top, padding-bottom, etc.

• Spacing can be adjusted using CSS properties like margin-top, margin-bottom, etc.

Components in React are reusable, independent pieces of code that manage their own state and can be composed together to build complex user interfaces.

• Components are the building blocks of React applications

• They can be class components or functional components

• Components can have their own state and lifecycle methods

• Components can be reused throughout the application

• Example:

  , ,

To center an item without flex and grid, use text-align center for inline elements and margin auto for block elements.

• For inline elements, use text-align: center on the parent element

• For block elements, use margin: 0 auto on the element you want to center

• For inline-block elements, set text-align: center on the parent and display: inline-block on the child

The 'this' keyword refers to the current object and is used to access its properties and methods.

• Used to refer to the current object in a method or constructor

• Can be used to call another constructor in the same class

• Can be used to call a method of the same object

• Can be used to call a method of a parent object

• Can be used to bind a function to a specific object

Data can be passed between components in Angular using input properties, output properties, services, and state management libraries like NgRx.

• Use input properties to pass data from parent to child components

• Use output properties to emit events from child to parent components

• Use services to create a shared data service that can be injected into multiple components

• Use state management libraries like NgRx for managing application state and sharing data between components

You can make a button disabled on click by adding a click event listener and setting the 'disabled' attribute.

• Add a click event listener to the button element

• Inside the event listener function, set the 'disabled' attribute of the button to true

Background position in CSS is used to specify the starting position of a background image.

• Background position can be set using keywords like top, bottom, left, right, center, or using specific pixel or percentage values.

• Example: background-position: top right;

• Example: background-position: 50% 50%;

Design a user-friendly landing page for a fictional e-commerce website showcasing products and promotions.

• Use a clean and modern layout with a prominent hero image to capture attention.

• Incorporate a navigation bar with categories like 'Home', 'Shop', 'About Us', and 'Contact'.

• Include a section for featured products with images, prices, and 'Add to Cart' buttons.

• Add promotional banners for discounts or seasonal sales to encourage purchases.

• Ensure the page is responsive, adapti...read more

Next.js is a React framework for building server-side rendered and static web applications with ease.

• Server-Side Rendering (SSR): Automatically renders pages on the server for better SEO and performance.

• Static Site Generation (SSG): Pre-renders pages at build time, improving load times (e.g., blog posts).

• API Routes: Allows building API endpoints within the application (e.g., /api/users).

• File-Based Routing: Simplifies routing by using the file system (e.g., pages/about.js maps...read more

CSS grids are a layout system that allows for responsive design using rows and columns.

• CSS Grid Layout is a two-dimensional layout system, enabling control over both rows and columns.

• It uses a grid container to define the grid structure with properties like 'display: grid'.

• Items within the grid can be placed precisely using grid lines, areas, and cells.

• Example: To create a simple grid, use 'grid-template-columns: repeat(3, 1fr);' for three equal columns.

• Grid can adapt to diff...read more

ES6 introduced significant improvements to JavaScript, enhancing syntax and functionality for developers.

• Arrow Functions: Shorter syntax for function expressions. Example: const add = (a, b) => a + b;

• Template Literals: Multi-line strings and string interpolation. Example: const greeting = `Hello, ${name}!`;

• Destructuring Assignment: Unpacking values from arrays or properties from objects. Example: const [x, y] = [1, 2];

• Default Parameters: Allowing named parameters to be initia...read more

Adding elements to an array can be done using methods like push, unshift, and splice in JavaScript.

• 1. Using push(): Adds one or more elements to the end of an array. Example: let fruits = ['apple', 'banana']; fruits.push('orange'); // ['apple', 'banana', 'orange']

• 2. Using unshift(): Adds one or more elements to the beginning of an array. Example: let fruits = ['apple', 'banana']; fruits.unshift('orange'); // ['orange', 'apple', 'banana']

• 3. Using splice(): Adds elements at a s...read more

Block elements take up the full width available, while inline-block elements only take up as much width as necessary.

• Block elements start on a new line and take up the full width available (e.g. <div>).

• Inline-block elements do not start on a new line and only take up as much width as necessary (e.g. <span>).

• Block elements can have margins and padding applied to all four sides, while inline-block elements only have horizontal margins and padding.

getElementsByClassName returns a live HTMLCollection of elements with the specified class name.

• Returns an HTMLCollection, which is an array-like object.

• HTMLCollection is live, meaning it updates automatically with DOM changes.

• Example: const elements = document.getElementsByClassName('myClass');

• Access elements using index: elements[0], elements[1], etc.

• Use Array.from() to convert HTMLCollection to an array for easier manipulation.

Event bubbling is the process in which an event triggered on a nested element is also triggered on its parent elements.

• Events in JavaScript propagate from the innermost element to the outermost element.

• During event bubbling, the event is first handled by the innermost element and then propagated to its parent elements.

• This allows for event delegation, where a single event handler can be used to handle events on multiple elements.

• Event.stopPropagation() can be used to stop the...read more

Web development is like building a house on the internet where people can visit and do things.

• Web development is creating websites and web applications using programming languages like HTML, CSS, and JavaScript.

• It involves designing how the website looks and works, and making sure it works well on different devices like computers and phones.

• Examples of web development include creating a website for a business, an online store, or a social media platform.

Object-Oriented Programming (OOP) concepts are fundamental for structuring code in a modular and reusable way.

• Encapsulation: Bundling data and methods that operate on the data within one unit (class). Example: A 'Car' class with properties like 'color' and methods like 'drive()'.

• Inheritance: Mechanism to create a new class using properties and methods of an existing class. Example: 'ElectricCar' inherits from 'Car'.

• Polymorphism: Ability to present the same interface for diffe...read more

The CSS box model is a design concept that describes how elements are rendered on a web page.

• The box model consists of content, padding, border, and margin.

• The content area is where the actual content of the element is displayed.

• Padding is the space between the content and the border.

• Border is a line that surrounds the padding and content.

• Margin is the space outside the border, separating the element from other elements.

• The box model allows for precise control over the layout...read more

The typeof() method in JavaScript returns the data type of a variable or expression.

• typeof() returns a string indicating the type of the operand.

• It can be used with variables, literals, or expressions.

• Common return values include 'number', 'string', 'boolean', 'object', 'function', and 'undefined'.