500+ Web Developer Interview Questions and Answers

Constraints in SQL are rules that are enforced on data columns in a table.

• Constraints ensure data integrity by enforcing rules on data columns

• Common constraints include NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK

• Example: NOT NULL constraint ensures a column cannot have a NULL value

Props are read-only data passed from parent to child components, while state is mutable data managed within a component.

• Props are used to pass data from parent to child components

• State is used to manage mutable data within a component

• Functional components are stateless and rely on props for data

• Class components can have state and props

• State can only be updated using setState() method

JavaScript is a programming language commonly used in web development for adding interactivity and dynamic content to websites.

• JavaScript is used for client-side scripting, allowing for interactive elements like forms, animations, and dynamic content.

• It can also be used for server-side scripting with Node.js to build backend applications.

• JavaScript frameworks like React, Angular, and Vue.js are popular for building dynamic and responsive web applications.

The connection variable in PHP is used to establish a connection to a database.

• The connection variable is created using the mysqli_connect() function

• It takes four parameters: host, username, password, and database name

• The variable is used to execute queries and retrieve results from the database

• It can be closed using the mysqli_close() function

Entity Relation model is a conceptual representation of the data structure and relationships in a database.

• It is used to design and visualize the database schema.

• Entities represent real-world objects or concepts.

• Relations define the associations between entities.

• Attributes describe the properties or characteristics of entities.

• Primary keys uniquely identify each entity in a relation.

• Foreign keys establish relationships between entities.

• ER diagrams are commonly used to represe...read more

Capgemini uses a variety of technologies depending on the project requirements.

• Capgemini uses Java, .NET, Python, and other programming languages.

• They also use various frameworks such as Angular, React, and Vue.js.

• For database management, they use Oracle, MySQL, and MongoDB.

• Capgemini also focuses on emerging technologies like AI, blockchain, and IoT.

• The specific technology used depends on the project requirements and client needs.

Abstract class in Java is a class that cannot be instantiated and may contain abstract methods.

• Cannot be instantiated directly

• May contain abstract methods that must be implemented by subclasses

• Can have both abstract and non-abstract methods

• Used for creating a template for other classes to extend

Java is a high-level programming language used for developing applications. There are four types of Java: Java SE, Java EE, Java ME, and JavaFX.

• Java is an object-oriented language.

• Java SE (Standard Edition) is used for general-purpose development.

• Java EE (Enterprise Edition) is used for developing enterprise applications.

• Java ME (Micro Edition) is used for developing applications for small devices.

• JavaFX is used for creating rich internet applications and multimedia content.

Appearance refers to the visual aspects of a website, including layout, colors, fonts, and images. WordPress design involves customizing the appearance of a website using themes and plugins.

• Appearance includes layout, colors, fonts, and images.

• WordPress design involves customizing themes and plugins.

• Themes determine the overall look and feel of a WordPress site.

• Plugins can add functionality and design elements to a WordPress site.

Elementor is a popular drag-and-drop page builder plugin for WordPress.

• Elementor allows users to easily create and customize websites without needing to know how to code.

• Users can drag and drop elements like text, images, and buttons to design their pages.

• Elementor offers a wide range of templates and widgets for customization.

• Users can also add custom CSS and HTML code for more advanced customization.

• Elementor is compatible with most WordPress themes and plugins.

Token generation and authentication process is a security mechanism used to verify the identity of a user.

• Token generation involves creating a unique token for each user upon successful login.

• The token is then stored in the user's browser or device.

• When the user makes subsequent requests, the token is sent along with the request.

• The server then verifies the token to authenticate the user.

• If the token is valid, the user is granted access to the requested resource.

• Examples of t...read more

Database can be connected to the front end using server-side scripting languages like PHP, Node.js, or Python.

• Use server-side scripting languages like PHP, Node.js, or Python to establish a connection between the database and front end.

• Utilize database management systems like MySQL, MongoDB, or PostgreSQL to store and retrieve data.

• Implement APIs to communicate between the front end and the database, allowing for data retrieval and manipulation.

• Ensure proper security measures...read more

HTML is a markup language used for creating the structure of web pages. CSS is a styling language used for designing the appearance of web pages.

• HTML stands for HyperText Markup Language

• HTML is used to create the structure of web pages using elements like <div>, <p>, <h1>, etc.

• CSS stands for Cascading Style Sheets

• CSS is used to style the appearance of web pages by defining properties like color, font size, layout, etc.

• Types of CSS include inline, internal, and external styles...read more

External CSS is stored in separate files while internal CSS is included within the HTML file.

• External CSS is linked to HTML using tag.

• Internal CSS is defined within

I will immediately take the website offline and assess the damage. Then I will work on fixing the vulnerabilities and restoring the website.

• Take the website offline

• Assess the damage

• Identify the vulnerabilities

• Fix the vulnerabilities

• Restore the website

• Implement security measures to prevent future attacks

Fat arrow function is a shorthand syntax for writing JavaScript functions.

• Also known as arrow function or lambda function

• Uses '=>' instead of 'function' keyword

• Does not have its own 'this' keyword

• Can be used for concise one-liner functions

• Example: const add = (a, b) => a + b;

One of the design patterns is the Singleton pattern.

• Singleton pattern ensures that only one instance of a class is created and provides a global point of access to it.

• It is useful when we need to limit the number of instances of a class to one.

• Example: Database connection class, where we need only one instance of the class to connect to the database.

• Another example is the Logger class, where we need only one instance to log messages throughout the application.

Use JavaScript to dynamically add an active class to all li elements.

• Select all li elements using document.querySelectorAll()

• Loop through the selected elements and add the active class using element.classList.add()

• Make sure to remove the active class from any previously active li elements if needed

To create a HTML file, you can use a text editor to write the code and save it with a .html extension.

• Open a text editor like Notepad, Sublime Text, or Visual Studio Code

• Write your HTML code including tags like <html>, <head>, <title>, <body>

• Save the file with a .html extension, for example index.html

• Open the file in a web browser to view the HTML content

An array is a data structure that stores multiple values in a single variable. There are three types of arrays in PHP: indexed arrays, associative arrays, and multidimensional arrays.

• Indexed arrays are arrays with numeric keys that start at 0.

• Associative arrays are arrays with named keys.

• Multidimensional arrays are arrays that contain other arrays as elements.

• Example: $colors = ['red', 'green', 'blue'];

• Example: $person = ['name' => 'John', 'age' => 30];

• Example: $matrix = [[1,...read more

React Router is a library that allows for routing in React applications, enabling navigation between different components.

• React Router is a popular routing library for React applications.

• It provides a way to handle navigation and rendering of different components based on the URL.

• React Router uses a declarative approach, allowing developers to define routes using components.

• It supports different types of routing, including browser history, hash history, and memory history.

• Rea...read more

React.js is a JavaScript library for building user interfaces.

• React.js is a popular front-end library developed by Facebook.

• It allows developers to build reusable UI components.

• React.js uses a virtual DOM for efficient rendering and updates.

• It follows a component-based architecture, making it easy to manage and maintain code.

• React.js supports server-side rendering for improved performance and SEO.

• It has a rich ecosystem with a large community and extensive documentation.

Keys in React list help identify and track individual items, improving performance and enabling efficient updates.

• Keys help React identify which items have changed, been added, or been removed in a list.

• They help improve performance by allowing React to reuse existing DOM elements instead of creating new ones.

• Keys also help maintain component state and prevent unnecessary re-rendering of components.

• Keys should be unique within the list and stable across re-renders to ensure p...read more

Laravel is a PHP framework that allows for easy creation of APIs with CRUD functionality.

• Laravel is a popular PHP framework known for its elegant syntax and powerful features.

• API stands for Application Programming Interface, which allows different software applications to communicate with each other.

• CRUD stands for Create, Read, Update, Delete - the basic operations of a database.

• Using Laravel, developers can easily create APIs that perform CRUD operations on a database.

Prevent page loading without login by implementing authentication and authorization.

• Implement a login system with authentication and authorization.

• Use session management to keep track of logged-in users.

• Check for session variables on every page load and redirect to login page if not found.

• Use server-side validation to prevent unauthorized access to pages.

• Encrypt sensitive data and use secure protocols like HTTPS.

• Implement timeout for inactive sessions to prevent session hijac...read more

PHP is a server-side scripting language used for web development.

• PHP is used to create dynamic web pages and web applications.

• It can interact with databases, handle forms, and manage sessions.

• PHP can be embedded into HTML code.

• Popular websites like Facebook, Wikipedia, and WordPress use PHP.

ES6 introduces new syntax and features to JavaScript.

• Arrow functions

• Template literals

• Let and const keywords

• Destructuring assignment

• Default parameters

• Rest and spread operators

• Classes

• Modules

Var is function-scoped and can be redeclared, while Let is block-scoped and cannot be redeclared.

• Var can be hoisted to the top of its scope, while Let cannot.

• Var can be declared without being initialized, while Let must be initialized before use.

• Var can cause unexpected behavior in loops, while Let avoids this issue.

• Var can be used to declare global variables, while Let cannot.

• Var can be redeclared within its scope, while Let cannot.

Class components are ES6 classes that extend React.Component while functional components are functions that return JSX.

• Class components have state and lifecycle methods while functional components don't.

• Functional components are simpler and easier to read while class components are more complex.

• Functional components are faster and have better performance than class components.

• Class components are used when we need to manage state or use lifecycle methods while functional comp...read more

HTML stands for Hypertext Markup Language and CSS stands for Cascading Style Sheets. There are different types of HTML and CSS.

• HTML - Hypertext Markup Language (types: HTML, HTML5)

• CSS - Cascading Style Sheets (types: CSS, CSS3)

To manage a payment gateway failure, identify the issue, communicate with the payment gateway provider, and implement a backup plan.

• Identify the issue causing the failure

• Communicate with the payment gateway provider to resolve the issue

• Implement a backup plan to ensure transactions can still be processed

• Monitor the situation to ensure the issue is fully resolved

Web programming involves creating and maintaining websites using programming languages and technologies.

• Web programming is the process of writing code to create and maintain websites.

• It involves using programming languages like HTML, CSS, and JavaScript.

• Web programming also includes server-side programming using languages like PHP, Python, or Ruby.

• Frameworks and libraries like React, Angular, and jQuery are commonly used in web development.

• Web programming also involves workin...read more

Constructor is used to create and initialize an object of a class.

• Constructor has the same name as the class.

• It is called automatically when an object is created.

• It can be used to set default values for object properties.

• It can also take parameters to initialize object properties.

• Example: class Person { constructor(name, age) { this.name = name; this.age = age; } }

• Example: let person1 = new Person('John', 30);

I took a break to pursue further education and gain more skills.

• I pursued a master's degree in computer science to gain more knowledge and skills.

• During my break, I also worked on personal projects to improve my coding abilities.

• I attended coding bootcamps and workshops to learn new technologies and frameworks.

• I wanted to ensure that I had a strong foundation before entering the workforce.

• My one year of experience has been very valuable and I have learned a lot in that time.

Assessing culture add involves evaluating a candidate's potential impact on the company's culture and values.

• Evaluate the candidate's values and beliefs to see if they align with the company's culture.

• Assess the candidate's communication style and how they interact with others in a team setting.

• Consider the candidate's past experiences and how they have contributed positively to team dynamics.

• Look for examples of how the candidate has demonstrated adaptability and openness to...read more

PHP is a server-side scripting language used for web development. Full form is Hypertext Preprocessor. Latest version is PHP 8.0.

• PHP is a popular scripting language for creating dynamic web pages.

• Full form of PHP is Hypertext Preprocessor.

• Latest version of PHP is PHP 8.0, released in November 2020.

The lifecycle of a .NET developer involves continuous learning, gaining experience, and adapting to new technologies.

• Continuous learning through courses, workshops, and self-study to stay updated with the latest .NET technologies.

• Gaining experience by working on various projects, both personal and professional, to improve skills and knowledge.

• Adapting to new technologies and trends in the .NET ecosystem, such as ASP.NET Core, Blazor, and Azure services.

• Networking with other d...read more

I believe improving the user experience by optimizing the website's loading speed and enhancing mobile responsiveness would greatly benefit the site.

• Optimize images and videos to reduce loading times

• Implement lazy loading for faster initial page load

• Ensure responsive design for seamless user experience on mobile devices

Triggers in SQL are special stored procedures that are automatically executed when certain events occur in a database.

• Triggers can be used to enforce business rules, maintain referential integrity, and automate tasks.

• There are two main types of triggers: Before Triggers and After Triggers.

• Example: A trigger can be set to automatically update a 'last_modified' column whenever a row is updated in a table.

A web developer should have knowledge of programming languages, web development frameworks, and design principles.

• Proficiency in programming languages such as HTML, CSS, JavaScript, and PHP

• Familiarity with web development frameworks like React, Angular, and Vue.js

• Understanding of design principles such as user experience and accessibility

• Ability to work with databases and APIs

• Continuous learning and keeping up with industry trends

Pseudo elements/children are CSS selectors that target specific parts of an element.

• Pseudo elements are denoted by a double colon (::) and are used to style a specific part of an element, such as the first letter or line of text.

• Pseudo children are denoted by a single colon (:), and are used to select a specific state of an element, such as when it is being hovered over or clicked.

• Examples of pseudo elements include ::before and ::after, which add content before or after an e...read more

A superclass is a class from which other classes inherit properties and methods.

• Superclass is also known as a parent class.

• Subclasses inherit attributes and behaviors from the superclass.

• Superclass promotes code reusability and helps in organizing code.

GitHub is a web-based platform for version control and collaboration that allows developers to store and manage their code.

• GitHub is used for version control, allowing developers to keep track of changes to their code over time

• It also provides collaboration tools, such as the ability to fork and merge code from other developers

• GitHub is widely used in the software development industry and is a valuable tool for managing code projects

• It offers features like issue tracking, cod...read more

C libraries provide pre-written code for common tasks in C programming language.

• C libraries contain pre-written code for common tasks such as string manipulation, memory allocation, and input/output operations.

• They are included in C programs using the #include directive.

• Examples of C libraries include stdio.h, string.h, and math.h.

• C libraries can be used to simplify programming tasks and improve code efficiency.

• They are often open source and can be modified and shared by deve...read more

ul is an HTML element used to create an unordered list, while ui is not a valid HTML element.

• ul is used to create a list of items without any specific order

• ui is not a valid HTML element and is likely a typo for ul or li

Calculate sum of elements at given index in array based on whether index is odd or even.

• Iterate through the array and check if the index is odd or even.

• Add the element to the sum if the index is odd, otherwise skip it.

• Return the final sum.

HTML is a markup language used to create the structure of a website.

• HTML stands for HyperText Markup Language.

• Use tags like <html>, <head>, <title>, <body> to structure content.

• Add elements like headings, paragraphs, images, links using tags.

• Use attributes like src, href, alt to specify additional information.

• Save the file with .html extension and open it in a web browser to view the website.