image.png

JavaScript (often abbreviated as JS) is a high-level, interpreted programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS.

It was created in just 10 days in 1995 by Brendan Eich while working at Netscape. Today, it runs on virtually every browser and has expanded to server-side and desktop/mobile application development.

Features:

  1. Interpreted Language: It is executed line-by-line by the JavaScript engine in the browser (or Node.js runtime)
  2. Dynamic Typing: You don't have to declare the variable type (e.g., string, number). The type is determined automatically at runtime.
let x = 10; // x is a number
x = "hello"; // now x is a string
  1. Versatility: It can be used for front-end (client-side), back-end (server-side with Node.js), mobile apps (React Native, Ionic), and desktop apps (Electron).
  2. Speed and Performance: Client-side JavaScript is very fast as it runs immediately within the browser. Modern Just-In-Time (JIT) compilation in engines like V8 (Chrome, Node.js) has made it incredibly performant.
  3. Ubiquity on the Client-Side: It is the only programming language that runs natively in all major web browsers. If you want interactive web pages.
  4. Single-Threaded: JavaScript uses a single-threaded model but manages asynchronous operations (like fetching data) efficiently using an event loop and a callback queue.
  5. Security: Regular JavaScript in web pages cannot access your system files without explicit user permission for security reasons, where as c++, JAVA, Server-side JavaScript (Node.js) and desktop applications built with JavaScript can access files.
  6. Garbage Collection (GC) is the automatic memory management process in JavaScript that frees up memory that is no longer being used by the program.

V8 JavaScript Engine

V8 is Google's open-source, high-performance JavaScript and WebAssembly engine, written in C++. It's the most widely known JavaScript engine that powers:

Node.js - JavaScript Runtime Environment

Node.js is an open-source, cross-platform JavaScript runtime environment that executes JavaScript code outside of a web browser. It's built on Chrome's V8 JavaScript engine