Frontend Development

Question 1

What is the difference between HTML and HTML5?

Answer 1

HTML5 introduced new elements like <header>, <footer>, <article>, and <section>, as well as support for multimedia (e.g., <audio> and <video>).

Question 2

Explain the box model in CSS.

Answer 2

The box model consists of content, padding, border, and margin. It defines how elements are structured and spaced.

Question 3

What is the difference between == and === in JavaScript?

Answer 3

== checks for value equality (with type coercion), while === checks for both value and type equality.

Question 4

What is React, and why is it used?

Answer 4

React is a JavaScript library for building user interfaces. It uses a virtual DOM for efficient updates and allows reusable components.

Question 5

What is the purpose of useState in React?

Answer 5

useState is a React hook that allows functional components to manage state.

Question 6

What is the difference between let, const, and var in JavaScript?

Answer 6

var is function-scoped and hoisted. let and const are block-scoped. const cannot be reassigned after declaration.

Question 7

What is the Virtual DOM?

Answer 7

The Virtual DOM is a lightweight copy of the actual DOM. It improves performance by minimizing direct DOM manipulations.

Question 8

What are CSS Flexbox and Grid?

Answer 8

Flexbox is for one-dimensional layouts (rows or columns), while Grid is for two-dimensional layouts (rows and columns).