About ReactJS.

Q1. What is React?
A1: React is a JavaScript library for building user interfaces.

Q2. Why React?
A2: One of the main benefits of using React JS is its potential to reuse components. It saves time for developers as they don't have to write various codes for the same features. Furthermore, if any changes are made in any particular part, it will not affect other parts of the application.

Q3. What is Virtual Dom?
A3: A virtual DOM is a lightweight JavaScript object which is a copy of the real DOM.

Q4. How does Virtual DOM work?

• A4: This Virtual DOM works in three simple steps-
  • Whenever any underlying data changes, the entire Ul is re-rendered in Virtual DOM representation.
  • Then the difference between the previous DOM representation and the new one is calculated
  • Once the calculations are done, the real DOM will be updated with only the things that have actually changed

Q5. What is Library?
A5: A JavaScript library is a library of pre-written JavaScript code that allows for easier development of JavaScript-based applications, especially for AJAX and other web-centric technologies.

Q6. What is AJAX?
A6: AJAX is a developer's dream because you can: Read data from a web server - after a web page has loaded, Update a web page without reloading the page, and Send data to a web server - in the background.

AJAX is not a programming language.

AJAX is a technique for accessing web servers from a web page.

AJAX stands for Asynchronous JavaScript And XML.

Q7. What is Framework?
A7: A JavaScript framework is a collection of JavaScript code libraries that provide a web developer with pre-written code for routine programming tasks. Frameworks are structures with a particular context and help you create web applications within that context.

It is completely possible to build strong web applications without JavaScript frameworks, but frameworks provide a template that handles common programming patterns. Each time you have to build an application, you don’t need to write code for every single feature from scratch. Instead, you can build upon an existing feature set.