Web-developer-Notes

  Basic Level: 1. What is JavaScript? JavaScript is a high-level, interpreted programming language used to make web pages interactive. 2. What are the data types in JavaScript? Primitive types: String, Number, Boolean, Null, Undefined Object types: Object, Array, Function 3. Explain the difference between let , const , and var . let and const are block-scoped, while var is function-scoped. const is used for constant values that shouldn't be reassigned. 4. What is the DOM? The Document Object Model represents the structure of a document as a tree of objects, allowing scripts to dynamically update content and style. 5. What is the difference between == and === ? == checks for equality after type coercion, while === checks for equality without type coercion. Intermediate Level: 1. Explain hoisting in JavaScript. Hoisting is a JavaScript behavior where variable and function declarations are moved to the top of their containing scope during compilation. 2.What is closure in Java...

  1.What is React? React is a JavaScript library for building user interfaces, particularly single-page applications where the user interface needs to be dynamic and responsive. 2.Explain the key features of React. React features include a virtual DOM for optimal performance, component-based architecture for reusability, JSX syntax for defining components, and unidirectional data flow through a concept known as props. 3.What is JSX? JSX (JavaScript XML) is a syntax extension for JavaScript recommended by React. It allows you to write HTML-like code in your JavaScript files, making it easier to describe the structure of React components. 4.What are React components? React components are the building blocks of a React application. They are reusable, self-contained pieces of code that manage their own state and can be composed to create complex UIs. 5.Explain the difference between functional components and class components. Functional components are stateless and are define...

  1.Explain the difference between cookies, sessionStorage, and localStorage. Cookies are small pieces of data sent from a website and stored on the user's computer. sessionStorage and localStorage are part of the Web Storage API, with the former storing data for the duration of a page session and the latter persisting data even after the browser is closed. 2.What is the purpose of the <canvas> element in HTML5, and how is it different from SVG? <canvas> is used for drawing graphics, such as charts or games, using JavaScript. Unlike SVG, which creates scalable vector graphics, <canvas> is raster-based and works with pixel data. 3.Explain the concept of responsive web design and how media queries are used. Responsive web design ensures that a web page adapts to different screen sizes and devices. Media queries in CSS are used to apply styles based on characteristics like screen width, height, or device orientation. 4.What is the role of the defer and async a...