Top 250 Web Development Interview Questions and Answers

Use Selenium WebDriver to find and count all text boxes on a web page.

• Use Selenium WebDriver to locate all text boxes on the web page

• Use findElements method with input tag and type attribute as text to find all text boxes

• Get the size of the list of elements to get the count of text boxes

Node.js is a server-side JavaScript runtime environment.

• Node.js is built on top of the V8 JavaScript engine from Google Chrome.

• It allows developers to write server-side code in JavaScript.

• Node.js has a non-blocking I/O model, making it efficient for handling large amounts of data.

• Node.js has a vast library of modules available through npm (Node Package Manager).

Optimizing a React app involves reducing bundle size, using lazy loading, and optimizing rendering performance.

• Reduce bundle size by code splitting and using dynamic imports

• Use lazy loading to load components only when needed

• Optimize rendering performance by using shouldComponentUpdate and PureComponent

• Use React.memo to memoize functional components

• Avoid unnecessary re-renders by using useMemo and useCallback

• Use performance profiling tools like React DevTools and Chrome DevTo...read more

To call REST APIs in Angular, use the HttpClient module and its methods like get(), post(), put(), delete().

• Import the HttpClientModule in your Angular module

• Inject the HttpClient service in your component or service

• Use the HttpClient methods to make HTTP requests to the REST APIs

• Handle the response using observables and subscribe to them

• Example: httpClient.get('https://api.example.com/data')

• Example: httpClient.post('https://api.example.com/data', postData)

Nodejs application can be deployed using various tools like Heroku, AWS, DigitalOcean, etc.

• Use a cloud platform like Heroku, AWS, DigitalOcean, etc.

• Create a production build of the application

• Configure environment variables

• Use a process manager like PM2 to manage the application

• Use a reverse proxy like Nginx to handle incoming requests

• Set up SSL/TLS certificates for secure communication

Absolute Xpath is the complete path from the root element to the desired element, while Relative Xpath is the path based on the current element.

• Absolute Xpath starts with a single slash (/) and is more specific but less flexible.

• Relative Xpath starts with a double slash (//) and is more flexible but less specific.

• Absolute Xpath is more prone to breaking if the structure of the page changes.

• Relative Xpath is easier to maintain and update as it is based on the element's positio...read more

Pseudo classes and pseudo elements are CSS selectors that target specific states or parts of an element.

• Pseudo classes target specific states of an element, such as :hover, :active, and :focus.

• Pseudo elements target specific parts of an element, such as ::before and ::after.

• Pseudo classes and pseudo elements are denoted by a colon (:) or double colon (::) preceding the selector.

• They can be used to add special effects, such as changing the color of a link when it is hovered ov...read more

Lazy Loading and Suspense are techniques used to improve performance by loading components and data only when needed.

• Lazy Loading delays the loading of non-critical resources until they are needed, reducing initial load time.

• Suspense allows components to wait for data to load before rendering, improving user experience.

• Lazy Loading and Suspense can be used together to optimize performance and user experience.

• Example: A website with a large image gallery can use Lazy Loading t...read more

API stands for Application Programming Interface. It is a set of rules and protocols that allows different software applications to communicate with each other.

• APIs are used to enable interaction between different software systems or components.

• They define the methods and data formats that applications can use to request and exchange information.

• APIs are commonly used in web development to integrate third-party services or access data from external sources.

• Examples of APIs in...read more

API stands for Application Programming Interface. It is a set of protocols and tools for building software applications.

• API allows different software applications to communicate with each other

• Types of API include: REST, SOAP, XML-RPC, JSON-RPC, and GraphQL

• REST API is the most commonly used type of API

• SOAP API uses XML for data exchange

• GraphQL API allows clients to specify the structure of the data they require

To import views in Django, you need to create a views.py file and import it in urls.py

• Create a views.py file in your Django app directory

• Define your views in the views.py file

• Import your views in urls.py using the 'from . import views' syntax

• Map your views to URLs in urls.py using the 'path()' function

PUT is used to update an existing resource, PATCH is used to partially update an existing resource, and POST is used to create a new resource.

• PUT replaces the entire resource with the new one, while PATCH only updates the specified fields

• PUT and PATCH are idempotent, meaning multiple identical requests will have the same effect as a single request

• POST is not idempotent and creates a new resource

• PUT and PATCH require the resource identifier in the URL, while POST does not

CORS in MVC is Cross-Origin Resource Sharing, a mechanism that allows restricted resources on a web page to be requested from another domain.

• CORS is a security feature implemented in web browsers to prevent cross-origin requests by default.

• It works by adding specific HTTP headers to the server's response, indicating which origins are allowed to access the resources.

• In MVC, CORS can be configured using the 'EnableCors' attribute on controllers or by configuring it in the 'Web....read more

Cookies in PHP are small text files that are stored on the user's computer to track and store information about the user's activities on a website.

• Cookies are used to remember user preferences and login information.

• They can be set, retrieved, and deleted using PHP's setcookie(), $_COOKIE, and setcookie() functions respectively.

• Cookies can have an expiration date and can be set to be accessible only over a secure connection.

• They are commonly used for tracking user behavior, pe...read more

ASP is a scripting language while ASP.NET is a web application framework.

• ASP is interpreted while ASP.NET is compiled

• ASP uses VBScript or JScript while ASP.NET uses C# or VB.NET

• ASP is outdated while ASP.NET is the current technology

• ASP.NET has better performance and security features than ASP

Redux middleware is a function that intercepts actions and can modify or dispatch new actions.

• Middleware can be used for logging, error handling, and asynchronous actions.

• Syntax: const middleware = store => next => action => { //middleware logic }

• Redux selectors are functions that extract specific data from the Redux store.

• Example: const getUserName = state => state.user.name;

Fragments in React.js are used to group multiple elements without adding an extra node to the DOM.

• Fragments are a way to group multiple elements without using a wrapper element.

• They help in avoiding unnecessary divs in the DOM.

• Fragments can improve performance by reducing the number of DOM nodes.

• They are useful when returning multiple elements from a component's render method.

• Fragments can be written using the syntax or the shorthand <> syntax.

The candidate is asked to write XPath and CSS selectors for elements on a webpage.

• XPath is a language used to navigate XML documents and can be used to locate elements on a webpage.

• CSS selectors are patterns used to select elements on a webpage based on their attributes.

• XPath selectors start with a forward slash (/) and can traverse the DOM hierarchy.

• CSS selectors can select elements based on their tag name, class, ID, or other attributes.

• Examples of XPath selector: /html/bod...read more

Laravel is a PHP web application framework that follows the Model-View-Controller (MVC) architectural pattern.

• Install Laravel using Composer

• Create a new Laravel project using the command 'laravel new project-name'

• Define routes in the 'routes/web.php' file

• Create controllers in the 'app/Http/Controllers' directory

• Define database connections in the '.env' file

• Use Laravel's built-in Blade templating engine for views

• Use Laravel's Eloquent ORM for database operations

DOM is a tree-like structure representing the HTML document, while Virtual DOM is a lightweight copy of the DOM.

• DOM is the actual representation of the HTML document in the browser's memory.

• Virtual DOM is a concept where a lightweight copy of the DOM is created and manipulated instead of directly modifying the actual DOM.

• Changes made to the Virtual DOM are compared with the actual DOM, and only the necessary updates are applied to the real DOM, resulting in better performance...read more

Clone a Todo Application UI using ReactJS, Sass

• Create a new ReactJS project using create-react-app

• Design the UI using Sass and implement it in ReactJS

• Use state and props to manage the todo list

• Add functionality to add, delete and mark tasks as complete

• Implement local storage to persist data

• Test the application thoroughly

Validations in the login feature of Salesforce ensure secure access and prevent unauthorized entry.

• Validations can be used to enforce password complexity requirements.

• IP range restrictions can be implemented to allow access only from specific locations.

• Two-factor authentication can be enforced for an additional layer of security.

• Login hours can be set to restrict access during specific time periods.

• Login IP restrictions can be applied to allow access only from trusted IP addr...read more

A controller to handle POST requests in a Spring REST API.

• Create a new class annotated with @RestController

• Define a method in the class annotated with @PostMapping

• Use @RequestBody annotation to bind the request body to a parameter

• Implement the logic to handle the POST request

• Return the response using ResponseEntity

Code a React app to change name state on a click of a button on code sandbox.

• Create a functional component with a state for name

• Render a button with an onClick event to update the name state

• Display the name state in the component

• Use CodeSandbox to test the app

Google reCAPTCHA is a security measure to prevent spam and bots. It cannot be solved in SEO.

• Google reCAPTCHA is designed to prevent automated bots from accessing websites.

• It is not possible to solve reCAPTCHA in SEO as it is a security measure.

• SEO analysts can optimize websites to improve user experience and reduce bounce rates.

• Using ethical SEO techniques can help improve website ranking and visibility.

• Avoid using black hat SEO techniques that violate Google's guidelines.

To connect a component to Redux store, we use the connect function from the react-redux library.

• Import the connect function from react-redux.

• Use the connect function to wrap the component and connect it to the Redux store.

• The connect function takes two parameters: mapStateToProps and mapDispatchToProps.

• mapStateToProps is a function that maps the state from the Redux store to the component's props.

• mapDispatchToProps is an optional function that maps the dispatch function to th...read more

Lazy loading is a technique to load modules on demand instead of loading everything at once.

• Lazy loading improves the initial load time of the application.

• It splits the application into smaller chunks that can be loaded when needed.

• In Angular, lazy loading is achieved by configuring the routes with loadChildren property.

• Syntax for routing path with lazy loading: { path: 'lazy', loadChildren: () => import('./lazy/lazy.module').then(m => m.LazyModule) }

A secure sign-in option can be designed by implementing multi-factor authentication and using encryption techniques.

• Implement multi-factor authentication such as using a password and a one-time code sent to the user's phone or email.

• Use encryption techniques such as hashing and salting to protect user passwords.

• Implement rate limiting to prevent brute force attacks.

• Use HTTPS protocol to encrypt data in transit.

• Regularly update and patch the sign-in system to address any secur...read more

Session is a way to store information (variables) on the server to be used across multiple pages.

• Session is used to maintain user-specific data across multiple pages.

• It is created when a user logs in and destroyed when the user logs out.

• Session data can be accessed and manipulated using the $_SESSION superglobal variable.

• Examples of session data include user ID, username, and shopping cart items.

Implicit objects in JSP servlets are pre-defined objects that can be accessed without any declaration.

• Implicit objects are created by the container and are available to the JSP page.

• Some of the implicit objects are request, response, session, application, out, pageContext, config, exception, etc.

• These objects can be used to perform various operations like accessing request parameters, setting attributes, forwarding requests, etc.

A status code is a two-digit code used in medical billing to indicate the status of a claim or service.

• Status codes are used to indicate whether a claim has been accepted, rejected, or is pending.

• They can also indicate the reason for a denial or rejection.

• Examples of status codes include 22 (processed, no payment), 29 (denied, unable to locate), and 30 (payment adjusted).

SAPUI5 is a JavaScript UI library for building web applications with a consistent user experience.

• Developed by SAP for building web applications

• Uses HTML5, CSS3, and JavaScript

• Provides a consistent user experience across devices

• Includes pre-built UI controls and templates

• Supports data binding and model-view-controller architecture

HTML5 is the latest version of the Hypertext Markup Language used for structuring and presenting content on the web.

• HTML5 introduces new elements and attributes for better structuring of web content.

• It supports multimedia elements like <video> and <audio> for seamless integration of media.

• HTML5 provides better support for mobile devices and responsive web design.

• It includes features like local storage, geolocation, and canvas for enhanced user experience.

• HTML5 is widely adopt...read more

Use CSS selector to locate element on webpage

• Use unique id or class names to locate element

• Use CSS selectors like 'id', 'class', 'name', 'tag name', etc.

• Use XPath if necessary for complex element locating

The number of tables generated after installing WordPress varies depending on the plugins and themes installed.

• The default installation of WordPress generates 12 tables in the database.

• Additional tables may be created by plugins and themes.

• Examples of additional tables include wp_users, wp_posts, wp_comments, etc.

Sessions and cookies are used to store and retrieve data in web applications.

• Sessions are used to store data on the server side and are identified by a unique session ID.

• Cookies are used to store data on the client side and are stored as small text files.

• Sessions are more secure as the data is stored on the server, while cookies can be manipulated by the client.

• Sessions are typically used to store sensitive information like user login details, while cookies are used for perso...read more

Fetch data from API to display array list of strings

• Use fetch() method to retrieve data from API

• Parse the response data using JSON.parse()

• Loop through the array and create a list element for each item

• Append the list elements to the DOM

TempData stores data for a single request while Session stores data for multiple requests.

• TempData is used to store data temporarily for a single request.

• Session is used to store data for multiple requests.

• TempData is cleared after a single request while Session data persists until the session expires or is cleared.

• TempData is useful for passing data between actions while Session is useful for maintaining user-specific data across multiple requests.

Exceptions in Rest APIs are handled using try-catch blocks and appropriate error responses.

• Use try-catch blocks to catch exceptions that may occur during API execution.

• Handle different types of exceptions separately to provide specific error responses.

• Return appropriate HTTP status codes and error messages in the response.

• Log the exception details for debugging purposes.

• Consider using a global exception handler to centralize exception handling logic.

Power BI reports can be embedded into SharePoint using the Power BI web part.

• Add the Power BI web part to the SharePoint page

• Enter the URL of the Power BI report in the web part properties

• Configure the web part settings to customize the report display

• Ensure that the SharePoint site and Power BI report are in the same organization

• Use the Power BI service to manage report permissions

Security in REST API can be handled by implementing authentication, authorization, encryption, and input validation.

• Implement authentication using tokens or OAuth2

• Implement authorization by defining roles and permissions

• Encrypt sensitive data using SSL/TLS

• Validate input data to prevent injection attacks

• Implement rate limiting to prevent DDoS attacks

UI policy and client script are both used in ServiceNow for controlling field behavior and data on forms.

• UI policy is used to dynamically change field properties, visibility, and mandatory status based on certain conditions.

• Client script is used to add custom logic and behavior to forms, such as field validation, calculations, and UI interactions.

• UI policy is executed on the server side, while client script is executed on the client side.

• UI policy is defined using a simple dr...read more

React JS is a JavaScript library for building user interfaces.

• Virtual DOM for efficient updates

• Component-based architecture for reusability

• JSX syntax for easy rendering

• Unidirectional data flow for predictable state management

• Server-side rendering for SEO optimization

Web services are used to exchange data between different applications over the internet.

• Allows communication between different platforms and programming languages

• Enables sharing of data and functionality

• Can be used for integration with third-party applications

• Examples include REST, SOAP, and JSON-RPC

The DOM (Document Object Model) in JavaScript is a programming interface for web documents. It represents the structure of a document as a tree of objects.

• The DOM is a representation of the HTML elements on a webpage.

• It allows JavaScript to interact with and manipulate the content and structure of a webpage.

• DOM methods like getElementById() and querySelector() are commonly used to access and modify elements on a webpage.

BS 4 engines are used for their improved fuel efficiency and reduced emissions.

• BS 4 engines comply with the latest emission norms set by the government.

• They have improved fuel efficiency due to advanced technology.

• BS 4 engines are more environment-friendly compared to older engines.

• They have better performance and durability.

• Examples of vehicles using BS 4 engines are Maruti Suzuki Swift, Hyundai Creta, etc.

Basic web development involves creating and maintaining websites using HTML, CSS, and JavaScript.

• Basic web development includes creating web pages using HTML, CSS, and JavaScript.

• It involves structuring the content of a website using HTML.

• CSS is used to style and format the web pages.

• JavaScript is used to add interactivity and dynamic features to the website.

• Web development also includes knowledge of web servers, databases, and frameworks.

• Examples of basic web development tas...read more

MERN stack is popular for full-stack development using MongoDB, Express, React, and Node.js.

• MERN stack includes MongoDB for database, Express for backend, React for frontend, and Node.js for server-side logic.

• It allows developers to build dynamic web applications efficiently.

• MERN stack provides a seamless integration between frontend and backend technologies.

• It is widely used in building single-page applications (SPAs) and progressive web apps (PWAs).

To add a new property in Google Analytics, follow these steps:

• Log in to your Google Analytics account

• Click on the Admin button in the bottom left corner

• Select the account and property where you want to add the new property

• Click on the Create Property button

• Follow the prompts to set up the new property

AngularJS is a JavaScript framework for building dynamic web applications.

• AngularJS is a client-side MVC framework.

• It allows developers to build single-page applications.

• It extends HTML with new attributes and tags.

• AngularJS uses two-way data binding to automatically synchronize data between the model and the view.

• It provides dependency injection and modularization features.

• Some popular examples of websites built with AngularJS are Gmail, YouTube, and Netflix.

Servlets are Java classes that handle HTTP requests and responses. XML is a markup language used for data exchange.

• Servlets are server-side components that generate dynamic web content.

• XML is used to store and transport data between systems.

• Servlets can be used to handle form submissions, authentication, and session management.

• XML can be used to define data structures, configuration files, and web services.

• Servlets are part of the Java EE specification, while XML is a languag...read more

ASP.NET MVC is a web application framework that implements the model-view-controller pattern.

• It separates an application into three main components: Model, View, and Controller.

• It provides better control over HTML, CSS, and JavaScript.

• It supports test-driven development and dependency injection.

• It is built on top of ASP.NET and uses the .NET Framework.

• Examples of websites built with ASP.NET MVC include Stack Overflow and GitHub.

Custom components in AEM can be created using the CRXDE Lite or Eclipse IDE.

• Create a new folder under /apps//components

• Create a new .content.xml file with the component's metadata

• Create a .html file with the component's markup

• Create a .clientlib file with the component's client-side dependencies

• Register the component in the OSGi bundle's pom.xml file

Request Delegate is a middleware component in ASP.NET Core pipeline.

• Request Delegate is responsible for handling HTTP requests and generating HTTP responses.

• It is a function that takes an HttpContext object as input and returns a Task.

• It can be used to modify the request or response, or to pass the request to the next middleware component in the pipeline.

• Example: app.Use(async (context, next) => { await next(); });

A search engine is a tool that allows users to search for information on the internet, while a directory is a curated list of websites organized by categories.

• Search engines use algorithms to crawl and index web pages, providing a comprehensive search experience.

• Directories are human-curated and organized by categories, providing a more focused and selective approach.

• Search engines provide results based on relevance and popularity, while directories provide a structured list ...read more

MPC stands for Model Provider Class and is used to define the data model in OData. DPC stands for Data Provider Class and is used to define the data access logic in OData.

• MPC is responsible for defining the data model and metadata for the OData service.

• DPC is responsible for defining the data access logic, such as reading and writing data, in the OData service.

• MPC is used to define the entity types, associations, and navigation properties in the OData service.

• DPC is used to i...read more

Different ways to send data view to controller

• Using form submission

• Using AJAX requests

• Using URL parameters

• Using cookies or local storage

• Using web sockets

WebAPI is a framework for building HTTP services that can be consumed by a broad range of clients.

• Create a new WebAPI project in Visual Studio

• Define API endpoints using HTTP verbs (GET, POST, PUT, DELETE)

• Use attribute routing to map URLs to actions

• Return data in JSON format

• Secure the API using authentication and authorization

Multiple databases can be connected to Drupal using the Database API and configuring settings.php file.

• Use the Database API to connect to additional databases

• Add the database connection details to settings.php file

• Use the db_set_active() function to switch between databases

• Use the db_query() function to execute queries on the selected database

React hooks simplify state management and lifecycle methods in functional components.

• Hooks allow functional components to have state and lifecycle methods

• They reduce the need for class components and HOCs

• Hooks make code more readable and easier to test

• Examples of hooks include useState, useEffect, and useContext

Optimize images, reduce HTTP requests, minify CSS and JS, use caching, and optimize database queries.

• Optimize images by compressing them and reducing their size.

• Reduce HTTP requests by combining multiple files into one.

• Minify CSS and JS by removing unnecessary characters.

• Use caching to store frequently accessed data.

• Optimize database queries by indexing tables and avoiding unnecessary joins.

jQuery post is a shorthand method for Ajax post in MVC.

• jQuery post is a shorthand method for Ajax post in MVC

• jQuery post uses the $.post() method while Ajax post uses $.ajax() method

• jQuery post is simpler and easier to use than Ajax post

• Both methods are used to send data to the server without reloading the page

ASP.NET follows a series of stages in its life cycle to process a request and generate a response.

• ASP.NET starts with the initialization stage where it creates an instance of the HttpApplication class.

• Next, it goes through the pipeline stages such as authentication, authorization, and caching.

• After that, it processes the request and generates a response.

• Finally, it goes through the cleanup stage where it releases resources and objects.

• ASP.NET also provides events for develope...read more

The different layers of Springboot application, webservers that come with Springboot, default webserver, changing default webserver, and configuring port on spring-boot.

• The different layers of Springboot application are presentation layer, service layer, business layer, and data access layer.

• The webservers that come with Springboot are Tomcat, Jetty, and Undertow.

• The default webserver is Tomcat.

• To change the default webserver, exclude the default starter and add the desired s...read more

There is no one-size-fits-all answer to this question as it depends on the specific project requirements.

• Python is a popular choice for backend development due to its simplicity and versatility.

• Java is another popular option for enterprise-level applications.

• Node.js is a popular choice for real-time applications and scalable systems.

• Ruby on Rails is a popular choice for rapid prototyping and web development.

• PHP is a widely used language for web development, particularly for W...read more

Developed a search engine UI using React framework in 30min

• Used React's useState and useEffect hooks to manage state and fetch data

• Implemented a search bar component with onChange event handler

• Displayed search results in a list using map function

• Added pagination for better user experience

Declaring connection string in middleware

• Connection string can be declared in appsettings.json file

• It can also be declared in environment variables

• Connection string can be injected using dependency injection

• Middleware can access connection string from IConfiguration object

Google Maps is a web mapping service developed by Google. It offers satellite imagery, street maps, 360° panoramic views of streets, real-time traffic conditions, and route planning.

• Provides detailed maps and satellite imagery of locations worldwide

• Offers real-time traffic updates and route planning

• Includes 360° panoramic views of streets

• Can be used for navigation and exploring new places

• Has features like Street View, indoor maps, and local business information

OAuth is an open standard for authorization that allows third-party applications to access user data without sharing passwords.

• OAuth stands for Open Authorization

• It allows users to grant access to their resources stored on one site to another site without sharing their credentials

• OAuth uses access tokens to authenticate and authorize requests

• It is widely used by social media platforms like Facebook, Twitter, and LinkedIn

• OAuth 2.0 is the latest version of OAuth

JWT stands for JSON Web Token, a compact and secure way of transmitting information between parties as a JSON object.

• JWT is used for authentication and authorization purposes.

• It consists of three parts: header, payload, and signature.

• The header contains the algorithm used to sign the token.

• The payload contains the claims or information being transmitted.

• The signature is used to verify the authenticity of the token.

• JWTs can be used in various scenarios, such as single sign-on ...read more

MVC stands for Model-View-Controller. Magento uses MVC architecture to separate business logic, presentation, and user input.

• Model represents the data and business logic

• View represents the presentation layer

• Controller handles user input and updates the model and view accordingly

• Magento uses the layout XML files to define the view layer

• Magento's controllers are responsible for handling requests and responses

• Magento's models are responsible for interacting with the database and...read more

Client side validation is done on the user's browser while server side validation is done on the server.

• Client side validation is done using JavaScript or HTML5.

• Server side validation is done using server-side scripting languages like PHP, Python, or Ruby.

• Client side validation is faster but less secure than server side validation.

• Server side validation is more secure but slower than client side validation.

• Examples of client side validation include checking for required field...read more

A fullstack developer is a software engineer who is proficient in both frontend and backend development.

• A fullstack developer has knowledge and skills in both frontend technologies (HTML, CSS, JavaScript) and backend technologies (server-side languages, databases).

• They are capable of working on all aspects of a software project, from designing and implementing user interfaces to developing server-side logic and managing databases.

• Fullstack developers are versatile and can han...read more

Angular is a JavaScript framework for building web applications with a modular architecture.

• Angular uses a component-based architecture to build reusable UI components

• It uses a declarative approach to define UI elements and their behavior

• Angular provides a powerful set of tools for data binding, dependency injection, and routing

• It follows the MVC (Model-View-Controller) pattern to separate concerns and improve maintainability

• Angular also supports server-side rendering for bet...read more

Ajax calls are asynchronous HTTP requests made by JavaScript to a server without reloading the page.

• Ajax stands for Asynchronous JavaScript and XML

• Used to update parts of a web page without reloading the entire page

• Can be used to fetch data from a server and display it on a web page

• Examples: Google Maps, Facebook News Feed

Query params can be passed through API by appending them to the URL after a '?' symbol.

• Add '?' symbol after the endpoint URL

• Add the parameter name followed by '=' and the value

• Separate multiple parameters with '&' symbol

• Example: https://api.example.com/users?id=123&name=John

CORS (Cross-Origin Resource Sharing) is a security feature that restricts web pages from making requests to a different domain.

• CORS issue occurs when a web page tries to access resources from a different domain

• It is a security feature implemented by web browsers to prevent cross-site scripting attacks

• CORS issue can be resolved by configuring the server to allow cross-origin requests or by using JSONP

• It can occur in AJAX requests, web fonts, images, and videos

To call server using servlet, we need to create a URL connection and send HTTP request.

• Create a URL object with the server URL

• Open a connection to the server using the URL object

• Set the request method (GET, POST, etc.) and any request headers

• Get the output stream from the connection and write any request data

• Read the response from the server using the input stream from the connection

• Close the connection and process the response data

Server side validation is the process of validating user input on the server before processing it.

• It ensures that the data received from the client is valid and secure.

• It prevents malicious attacks and data breaches.

• It reduces the load on the client-side and improves performance.

• Examples include checking for required fields, data type, length, and format.

• It is an essential part of web application security.

EventLoop is a mechanism in Node.js that allows non-blocking I/O operations to be performed asynchronously.

• EventLoop is responsible for handling all I/O operations in Node.js

• It continuously checks the event queue for any new events to be processed

• It executes callbacks when an event is triggered

• It allows Node.js to handle multiple requests simultaneously

• It prevents blocking of the main thread

URL mode is used to test the performance of a specific URL, while HTML mode is used to test the performance of the entire HTML page.

• URL mode focuses on a single URL, measuring response time and other metrics specific to that URL.

• HTML mode simulates user behavior on the entire HTML page, including loading all resources like images, scripts, and stylesheets.

• URL mode is useful for pinpointing performance issues with specific URLs, while HTML mode provides a more comprehensive vi...read more

BS4 and BS6 are emission norms set by the government to regulate the amount of pollutants emitted by vehicles.

• BS4 stands for Bharat Stage 4 and BS6 stands for Bharat Stage 6.

• BS6 is the latest emission standard set by the government, which is more stringent than BS4.

• BS6 compliant vehicles emit lower levels of pollutants such as nitrogen oxides, carbon monoxide, hydrocarbons, and particulate matter compared to BS4 vehicles.

• BS6 compliant vehicles also have advanced technologies ...read more

MVC is a design pattern that separates an application into three interconnected components: Model, View, and Controller.

• Model represents the data and business logic of the application

• View is responsible for rendering the user interface

• Controller handles user input and updates the model and view accordingly

• In ROR, the model is typically represented by a database table, the view is an HTML template, and the controller is a Ruby class

• MVC helps to keep code organized, maintainabl...read more

Front controller is a design pattern used in Spring MVC to handle incoming requests and route them to appropriate handlers.

• Front controller acts as a central point of control for handling requests in Spring MVC.

• It receives all incoming requests and delegates them to appropriate handlers called controllers.

• Front controller provides a consistent way to handle requests and perform common tasks like authentication, logging, etc.

• In Spring MVC, the DispatcherServlet acts as the fro...read more

Middleware is software that sits between an application and the operating system, providing services to the application beyond those provided by the operating system.

• Middleware is a pipeline of components that can handle requests and responses.

• It can be used for authentication, logging, caching, and more.

• Middleware can be added to the pipeline using the Use() method in the Startup class.

• Examples of middleware in .NET Core include the Authentication middleware, the CORS middle...read more

Lazy loading is a technique to defer loading of non-critical resources until they are needed.

• Lazy loading improves page load time and performance.

• It is commonly used for images, videos, and other media files.

• To call HTTP requests from one component to another, we can use Angular's HttpClient service.

• We can inject the HttpClient service in the constructor of the component and use its methods to make HTTP requests.

• We can also use Angular's @Input and @Output decorators to pass ...read more

API URLs can be hidden by using environment variables and managing different URLs for different staging environments.

• Use environment variables to store API URLs

• Create separate environment files for different staging environments

• Set the appropriate API URL in the environment file for each staging environment

• Access the API URL from the environment variable in the code

Yes, I know IIS.

• I have experience in configuring and managing IIS servers.

• I am familiar with setting up websites, application pools, and virtual directories.

• I have worked with IIS versions 6, 7, and 8.

• I am comfortable troubleshooting issues related to IIS.

• I have used IIS to host various web applications, including ASP.NET and PHP applications.

Express.js is a popular Node.js web framework used for building web applications. Body-parser is a middleware used to parse incoming request bodies.

• Express.js is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

• It provides a way to handle HTTP requests and responses, routing, middleware, and more.

• Body-parser is a middleware used to parse incoming request bodies in a middleware before your handlers,...read more

Optimisation in web involves improving website performance for better user experience.

• Minimize HTTP requests by combining files, using CSS sprites, and reducing scripts

• Enable browser caching to reduce server load and load times

• Optimize images by resizing and compressing them

• Use a content delivery network (CDN) to distribute content geographically for faster loading times

• Minimize redirects and eliminate unnecessary plugins or scripts

To deploy a website, you need to choose a hosting provider, upload your files, and configure your domain name.

• Choose a hosting provider that suits your needs and budget

• Upload your website files to the hosting provider's server

• Configure your domain name to point to the hosting provider's server

• Test your website to ensure it is working properly

JSP and Servlet are Java technologies used for creating dynamic web pages and handling HTTP requests and responses.

• JSP stands for JavaServer Pages and is used for creating dynamic web pages that can interact with server-side data and logic.

• Servlet is a Java program that runs on a web server and handles HTTP requests and responses.

• JSP and Servlet work together to create dynamic web applications that can generate HTML, process user input, and interact with databases.

• JSP pages a...read more

Implementing Spring security with JWT token involves configuring security filters and authentication providers.

• Add dependencies for Spring Security and JWT

• Configure security filters to validate JWT tokens

• Implement authentication provider to authenticate users

• Generate and sign JWT tokens for successful authentication

• Example: https://www.baeldung.com/spring-security-jwt

A module is a container for a group of related components, directives, pipes, and services.

• Modules help organize an application into cohesive blocks of functionality.

• They can be imported and exported to share functionality between modules.

• Angular has a built-in module called the AppModule, which is the root module of an Angular application.

• Modules can be lazy loaded to improve performance.

• Modules can have their own providers to provide services specific to that module.

300 represents multiple choices and 301 represents moved permanently.

• 300 status code represents multiple choices, indicating that the requested resource has multiple representations available.

• 301 status code represents moved permanently, indicating that the requested resource has been permanently moved to a new URL.

• Both status codes are used in HTTP responses to indicate the status of a requested resource.

• Examples of 300 status code include a webpage with multiple language op...read more

HTML program for form validation

• Use HTML form elements like input, select, textarea

• Use JavaScript for validation

• Check for required fields, email format, password strength, etc.

Browsers use rendering engines to interpret HTML, CSS, and JavaScript to display web pages.

• Browsers use rendering engines to interpret HTML, CSS, and JavaScript.

• The rendering engine parses the HTML and creates a DOM tree.

• The rendering engine then applies CSS rules to the DOM tree to create a render tree.

• The render tree is then laid out to determine the position of each element on the page.

• Finally, the rendering engine paints the render tree on the screen.

• JavaScript can manipu...read more