*Top 50 Frontend Developer interview Questions* *Give me 20+ Reaction "❤️❤️" On this Message For Next Questions* *Basic Level Questions* What is HTML, and why is it used? What are semantic HTML tags? Can you give examples? Explain the difference between id and class in HTML. What is CSS, and how does it enhance a webpage? What are the different types of CSS (inline, internal, external)? What is the difference between relative, absolute, and fixed positioning in CSS? How does the box model work in CSS? What is the difference between em, rem, %, and px units in CSS? What are pseudo-classes and pseudo-elements in CSS? What is JavaScript? How does it differ from Java? *Intermediate Level Questions* What are the different types of JavaScript data types? What is the difference between == and === in JavaScript? Explain event delegation in JavaScript. What is the purpose of the this keyword in JavaScript? What are closures in JavaScript, and why are they useful? How does the DOM work, and what is its significance? What are cookies, session storage, and local storage? How do they differ? What is responsive web design, and how can you achieve it? What is a media query in CSS? Can you provide an example? What is the difference between let, var, and const in JavaScript? *Advanced Level Questions* What is the virtual DOM, and how does it differ from the real DOM? Explain React’s lifecycle methods. What is the purpose of state and props in React? What are hooks in React? Can you explain useState and useEffect? What is Redux, and how does it work? How would you optimize the performance of a React application? What is TypeScript, and how is it different from JavaScript? What is Webpack, and why is it used? How does the async and await feature in JavaScript work? What is a REST API, and how do you consume it in frontend development? *CSS and Design-Related Questions* What is the difference between Flexbox and Grid in CSS? How do you create a mobile-first design? What is z-index, and how does stacking context work in CSS? What are CSS transitions and animations? Can you provide examples? What are SVGs, and why are they preferred over other image formats? *Performance Optimization Questions* What is lazy loading, and how is it implemented? How do you optimize website performance for faster loading? What is critical rendering path, and why is it important? What are Content Delivery Networks (CDNs), and how do they help? What tools do you use for debugging performance issues in frontend? *General/Other Questions* Explain Cross-Origin Resource Sharing (CORS) and its importance. What is accessibility (a11y), and why is it important in web development? What is Progressive Web App (PWA)? What are its benefits? What are some common security vulnerabilities in frontend development, and how can you prevent them? What is Service Worker, and how does it work in PWAs? What are the differences between SSR (Server-Side Rendering) and CSR (Client-Side Rendering)? How do you handle version control in projects? Do you use Git? What is the difference between GET and POST methods in HTTP? How do you debug JavaScript code? What tools do you use? What is Lighthouse, and how can it improve your website?