500+ Web Developer Interview Questions and Answers

var is function-scoped and let is block-scoped.

• var declarations are hoisted to the top of their scope, while let declarations are not.

• var can be redeclared in the same scope, while let cannot.

• let variables are not accessible before they are declared, while var variables are.

• let variables have a temporal dead zone, while var variables do not.

• let is recommended for use in modern JavaScript.

Event loop in JS manages the execution of code and handles asynchronous tasks.

• JS is single-threaded, so event loop helps manage tasks without blocking the main thread.

• Asynchronous programming allows non-blocking execution of code.

• Callbacks, Promises, and Async/Await are common ways to handle asynchronous tasks.

• Example: setTimeout() function uses event loop to execute code after a specified delay.

OOP is a programming paradigm based on the concept of objects, which can contain data in the form of fields and code in the form of procedures.

• OOP focuses on creating objects that interact with each other to solve complex problems.

• Fundamental concepts include classes, objects, inheritance, encapsulation, and polymorphism.

• Classes are blueprints for creating objects, while objects are instances of classes.

• Inheritance allows classes to inherit attributes and methods from other c...read more

An array is a data structure that stores a collection of elements of the same type. There are different types of arrays such as one-dimensional, multi-dimensional, and associative arrays.

• One-dimensional array: Stores elements in a single row or column.

• Multi-dimensional array: Stores elements in multiple rows and columns.

• Associative array: Uses key-value pairs to store elements.

• Example: ['apple', 'banana', 'orange']

Absolute positioning is relative to the nearest positioned ancestor, while fixed positioning is relative to the viewport.

• Absolute positioning is based on the nearest positioned ancestor, while fixed positioning is based on the viewport.

• Absolute positioned elements are removed from the normal flow of the document, while fixed positioned elements stay in the same position even when the page is scrolled.

• Examples: Absolute positioning can be used to position a popup menu within a...read more

Class is used to style multiple elements, while Id is used to style a single element.

• Class can be used multiple times in a document, while Id should be unique.

• Class is denoted by a period (.), while Id is denoted by a hash (#).

• Example: <div class='container'> vs <div id='header'>

Yes, I have experience with web services.

• I have worked with RESTful APIs to retrieve and manipulate data from external sources.

• I have used SOAP web services to integrate different systems and exchange data.

• I am familiar with JSON and XML formats commonly used in web services.

• I have implemented authentication and authorization mechanisms for secure web service access.

• I have used tools like Postman or cURL to test and debug web services.

display flex is used for creating flexible layouts, while display inline-block is used for creating inline elements with block-level properties.

• display flex is used to create flexible layouts that can adapt to different screen sizes and orientations

• display inline-block is used to create inline elements that can have block-level properties like width and height

• display flex allows for easy alignment and distribution of elements within a container

• display inline-block allows for ...read more

My career goal in the next five years is to become a senior web developer and lead a team of developers in creating innovative and impactful web solutions.

• Advance my skills in web development by learning new technologies and frameworks

• Take on more challenging projects to expand my experience and expertise

• Work towards a leadership role within the development team

• Contribute to the success of the company by delivering high-quality web solutions

• Attend industry conferences and net...read more

A database is a collection of data organized in a structured way, while a data structure is a way to store and organize data within a program or system.

• Database is a collection of related data stored in a structured format, like tables in SQL.

• Data structure is a way to organize and store data within a program, like arrays or linked lists.

• Databases are used to store and retrieve data efficiently, while data structures help in manipulating and accessing data within a program.

• Ex...read more

Social media login can be added through OAuth authentication by integrating APIs of respective social media platforms.

• Choose the social media platforms to integrate with

• Register the application with the chosen platforms to get API keys

• Use OAuth authentication to allow users to login with their social media accounts

• Store the user data obtained from social media platforms in the application database

Answering questions related to joins, group by, responsive term in bootstrap, and inserting data using XML.

• Types of joins include inner join, left join, right join, and full outer join.

• Group by is used to group data based on a specific column in a table.

• Responsive term in bootstrap refers to the ability of a website to adjust its layout based on the screen size of the device.

• To insert data using XML, one can use the INSERT INTO statement with the OPENROWSET function.

Angular is a front-end framework developed by Google, while React is a JavaScript library for building user interfaces.

• Angular is a full-fledged front-end framework with its own ecosystem, while React is a JavaScript library focused on building UI components.

• Angular uses TypeScript, while React uses JavaScript.

• Angular has a two-way data binding feature, while React uses a one-way data flow.

• Angular has a steep learning curve due to its complexity, while React is easier to lear...read more

Use a subquery to find the second largest element in a dataset.

• Use a subquery to select the maximum value from the dataset.

• Then use another subquery to select the maximum value that is less than the maximum value found in the first subquery.

CSS can be applied inline within HTML elements or externally in a separate file.

• Inline CSS is applied directly within the HTML element using the 'style' attribute

• Internal CSS is included within the

I would design and develop the student register with admission fees using a database and a web application.

• Create a database to store student information and admission fees

• Develop a web application with a user interface for students to register and pay fees

• Include validation for input fields and payment processing

• Implement security measures to protect sensitive information

• Provide reporting and analytics for administrators to track student enrollment and revenue

Client side programming runs on user's browser while server side programming runs on server.

• Client side programming involves HTML, CSS, and JavaScript.

• Server side programming involves languages like PHP, Python, and Ruby.

• Client side programming is responsible for user interface and user experience.

• Server side programming is responsible for server management and database handling.

A scripting language is a programming language that is used to write scripts, which are small programs that automate tasks.

• Scripting languages are interpreted rather than compiled

• They are often used for tasks such as web development, system administration, and automation

• Examples of scripting languages include JavaScript, Python, Ruby, and PHP

The 'id' selector is unique to one element on a page, while the 'class' selector can apply to multiple elements.

• ID selector is denoted by # in CSS, while class selector is denoted by .

• ID should be unique on a page, while class can be used for multiple elements

• ID selector has higher specificity than class selector

Drupal has 5 conceptual layers: Presentation, Data, Module, Node, and Field.

• Presentation layer handles the look and feel of the site

• Data layer manages the storage and retrieval of data

• Module layer provides additional functionality through modules

• Node layer handles content types and their display

• Field layer manages the fields that make up content types

To register customer post types in functions.php, use the register_post_type() function.

• Use the register_post_type() function with the desired arguments.

• Add the function to the functions.php file of your theme or plugin.

• Example: register_post_type('book', ['public' => true, 'label' => 'Books']);

ACID property ensures database transactions are reliable and consistent.

• ACID stands for Atomicity, Consistency, Isolation, and Durability.

• Atomicity ensures that a transaction is treated as a single, indivisible unit.

• Consistency ensures that a transaction brings the database from one valid state to another.

• Isolation ensures that concurrent transactions do not interfere with each other.

• Durability ensures that once a transaction is committed, it will remain so even in the face o...read more

State is mutable and managed within a component, while props are immutable and passed from parent to child components.

• State is used to manage internal data within a component.

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

• State can be changed using the setState() method.

• Props are read-only and cannot be modified by the component receiving them.

• State is local to a component, while props can be accessed by multiple components.

• Example: State can be used to store for...read more

HTML container tags are used to group and define sections of content on a webpage.

• The <div> tag is used to group elements together and define a section of content.

• The <span> tag is used to group inline elements together.

• The <section> tag is used to define sections of content within a webpage.

• The <header> tag is used to define a header section within a webpage.

• The <footer> tag is used to define a footer section within a webpage.

Pagination using CSS3 can be achieved by using the 'display: flex' property along with 'flex-wrap' and 'justify-content' properties.

• Use 'display: flex' property to create a flexible layout for pagination

• Set 'flex-wrap: wrap' to allow the pagination items to wrap to the next line when there is not enough space

• Use 'justify-content: center' to horizontally center the pagination items on the page

Session state in HTTP refers to the data stored on the server about a user's interactions during a session.

• Session state allows the server to remember information about a user's interactions during a session.

• It is typically stored in server-side memory or a database.

• Session state is used to maintain user authentication, shopping cart contents, and other user-specific data.

• Cookies are often used to maintain session state by storing a session ID on the client side.

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

• HTML stands for HyperText Markup Language

• It is used to define the structure of content on a web page

• HTML elements are used to create headings, paragraphs, links, images, and more

• It is the foundation of web development and is essential for creating websites

forEach loops through elements while map() returns a new array.

• forEach() executes a provided function once for each array element.

• map() creates a new array with the results of calling a function for every array element.

• forEach() does not return anything while map() returns a new array.

• map() can be used to transform an array into a new array with modified values.

• forEach() is useful for iterating over an array and performing some operation on each element.

The flex property in CSS is used to set the length of a flexible item along the main axis of a flex container.

• The flex property is a shorthand for flex-grow, flex-shrink, and flex-basis.

• It determines how much a flex item will grow or shrink to fill the available space.

• Example: flex: 1 1 50%; sets flex-grow to 1, flex-shrink to 1, and flex-basis to 50%.

jQuery is a JavaScript library that simplifies HTML DOM traversal and manipulation, and AJAX is a technique used to create fast and dynamic web pages without reloading the entire page.

• jQuery is a popular JavaScript library used for DOM manipulation and event handling

• AJAX (Asynchronous JavaScript and XML) is a technique used to create fast and dynamic web pages without reloading the entire page

• jQuery provides a simplified way to use AJAX through its $.ajax() method

• AJAX can be ...read more

Yes, I am familiar with WordPress, HTML, CSS, and Bootstrap.

• I have experience working with WordPress to create and customize websites.

• I am proficient in HTML for structuring web pages.

• I have knowledge of CSS for styling and formatting web content.

• I am familiar with Bootstrap for responsive web design.

• I have created websites using these technologies in the past.

A library is a collection of functions or classes that can be called by an external program, while a framework is a set of libraries that provide a structure for building applications.

• A library is used when you want to perform specific tasks, while a framework provides a structure for building an entire application.

• Libraries are more flexible and allow for more customization, while frameworks have a specific structure that must be followed.

• Examples of libraries include jQuery...read more

Mutable data types can be changed after creation, while immutable data types cannot be changed.

• Mutable data types: lists, dictionaries

• Immutable data types: strings, tuples

• Changing a mutable data type will modify the original object, while changing an immutable data type will create a new object

React is a JavaScript library for building user interfaces.

• React is a JavaScript library developed by Facebook.

• React uses a virtual DOM for better performance.

• React is component-based, making it easier to reuse code.

• React is mainly used for building single-page applications.

• Angular is a full-fledged framework for building web applications.

• Angular uses two-way data binding, while React uses one-way data flow.

• Angular has a steeper learning curve compared to React.

Normalization is the process of organizing data in a database to reduce redundancy and dependency.

• Normalization helps to eliminate data redundancy and inconsistencies.

• It involves breaking down a table into smaller tables and defining relationships between them.

• Normalization is achieved through a series of normal forms, such as first normal form (1NF), second normal form (2NF), and so on.

• Normalization ensures data consistency and improves database performance.

• Example: A custom...read more

Java is a popular programming language known for its versatility and platform independence.

• Java is an object-oriented programming language used for developing a wide range of applications, from web and mobile apps to enterprise systems.

• It is platform-independent, meaning that Java code can run on any device that has a Java Virtual Machine (JVM) installed.

• Java is known for its security features, which help protect against viruses and other malicious attacks.

• It has a large stan...read more

Python's main syllabus includes data types, control structures, functions, modules, classes, and libraries.

• Data types such as integers, floats, strings, lists, tuples, dictionaries

• Control structures like if-else statements, loops

• Functions for code reusability

• Modules for organizing code

• Classes for object-oriented programming

• Libraries like NumPy, Pandas, and Matplotlib for data manipulation and visualization

Synchronous and asynchronous in React refer to the way in which code is executed and managed.

• Synchronous operations block the execution of code until the operation is completed.

• Asynchronous operations allow the code to continue running while waiting for the operation to complete.

• In React, asynchronous operations are commonly used for fetching data from APIs or handling user interactions.

• Examples of asynchronous operations in React include fetching data using fetch or axios, h...read more

Asynchronous programming allows tasks to run independently, improving performance and responsiveness.

• Asynchronous programming helps prevent blocking of the main thread, allowing other tasks to continue running.

• It is commonly used in web development for tasks such as fetching data from APIs or handling user input.

• Examples include using JavaScript's async/await or Promises to handle asynchronous operations.

• Asynchronous programming can improve the overall user experience by maki...read more

I have extensive experience in Shopify custom app development, including creating custom features and integrations.

• Developed custom apps to enhance user experience and streamline processes

• Integrated third-party APIs to add new functionalities

• Optimized app performance and resolved technical issues

• Worked on projects such as custom product builders and subscription services

Some common hooks used in React.js are useState, useEffect, useContext, and useRef.

• useState - for managing state in functional components

• useEffect - for handling side effects in functional components

• useContext - for accessing context in functional components

• useRef - for accessing DOM elements or values in functional components

To find the largest number in an array, loop through the array and compare each element with a variable holding the current largest number.

• Initialize a variable with the first element of the array

• Loop through the array and compare each element with the variable holding the current largest number

• If the current element is larger than the variable, update the variable with the current element

• After the loop, the variable will hold the largest number in the array

Multilevel inheritance is a concept in object-oriented programming where a class inherits properties and methods from another class, which in turn inherits from another class.

• Multilevel inheritance involves creating a hierarchy of classes, where each class inherits from the class above it.

• The derived class inherits the properties and methods of the base class, and can also add its own unique properties and methods.

• This type of inheritance allows for code reusability and promo...read more

My driving force is my passion for creating innovative and user-friendly web applications.

• Passion for creating innovative and user-friendly web applications

• Desire to constantly learn and improve my skills

• Enjoyment of problem-solving and finding creative solutions

• Satisfaction in seeing the end result and how it benefits users

• Motivation to stay up-to-date with the latest technologies and trends

The 'this' keyword is used in JavaScript to refer to the object that is currently executing the code.

• It allows access to the object's properties and methods within its scope.

• It is commonly used in object-oriented programming to refer to the current instance of a class.

• The value of 'this' is determined by how a function is called, and it can change dynamically.

• It is often used in event handlers, constructor functions, and prototype methods.

HTML is a markup language for creating web pages, CSS is used for styling. Tables in HTML are used to display data in rows and columns. Frameworks are used for faster development.

• HTML is a markup language used for creating the structure of web pages

• CSS is used for styling the HTML elements

• Tables in HTML are created using the <table>, <tr>, and <td> tags

• Frameworks like Bootstrap are used to provide pre-designed components and styles for faster development

To check if a string is palindrome, compare it with its reverse.

• Remove all non-alphanumeric characters and convert to lowercase for accurate comparison.

• Use two pointers, one at the start and one at the end, and compare the characters at each position.

• If all characters match, the string is a palindrome.

• Example: 'A man, a plan, a canal: Panama' is a palindrome.