🔹 React.js
Q1: What is React.js?
A: React.js is an open-source JavaScript library used for building user interfaces, especially single-page applications. It allows developers to create reusable UI components.
Q2: What is JSX?
A: JSX stands for JavaScript XML. It allows you to write HTML-like syntax in JavaScript, which is then transformed into React elements.
Q3: What are components in React?
A: Components are independent, reusable pieces of UI in React. They can be functional or class-based.
Q4: What is the difference between state and props in React?
A: Props are used to pass data from parent to child components, and are read-only. State is used for data that changes over time and is managed within the component.
🔹HTML
Q5: What is <!DOCTYPE html>?
A: It is a declaration that defines the document type and version of HTML being used. In HTML5, it ensures the browser renders the page in standards mode.
Q6: What is the difference between <div> and <span>?
A: <div> is a block-level element used for layout. <span> is an inline element used to style small chunks of content.
Q7: What are semantic HTML tags?
A: Semantic tags like <header>, <footer>, <article> clearly describe the role of the content inside them, improving accessibility and SEO.
🔹 CSS
Q8: What’s the difference between CSS and CSS3?
A: CSS3 is the latest version of CSS, introducing new features like animations, transitions, flexbox, and media queries.
Q9: What are CSS selectors?
A: CSS selectors are patterns used to select and style elements, such as .class, #id, element, etc.
Q10: What is a media query in CSS?
A: Media queries allow you to apply different styles depending on the device’s screen size or resolution.
🔹 JavaScript
Q11: What is ECMAScript?
A: ECMAScript is the standardized version of JavaScript defined by ECMA International.
Q12: What is the difference between var, let, and const?
A: var is function-scoped, let and const are block-scoped. const values cannot be reassigned.
Q13: What is a callback function in JavaScript?
A: A callback function is a function passed as an argument to another function and is executed after the parent function finishes.
👉The Next Questions-2: FRONTEND
