JS

Js, commonly known as JavaScript or JS, is a high-level, dynamic programming language that enables interactive features on web pages and applications. Although primarily executed in web browsers, it is also used on servers and in non-browser environments through various runtimes. Js is a core technology of the World Wide Web, alongside HTML and CSS, and is used to implement client-side behavior, manipulate the document object model, and handle user events.

Js originated in 1995, created by Brendan Eich at Netscape, and over time was standardized as ECMAScript by ECMA International to promote cross-platform compatibility. The language has evolved through many editions, with ES2015 (often called ES6) introducing major features such as classes, modules, let and const declarations, and arrow functions. Updates since then have continued to add syntax and runtime improvements.

Key features include prototype-based inheritance, first-class functions, dynamic typing, and a multi-paradigm approach that supports imperative, object-oriented, and functional programming. JavaScript uses a single-threaded event loop and supports asynchronous programming through callbacks, promises, and async/await. It runs in managed environments with automatic garbage collection.

Environment and ecosystem: In browsers, JavaScript interacts with the Document Object Model (DOM) and Browser Object Model (BOM) to create dynamic pages. On the server, Node.js provides a runtime with access to the file system and network. The ecosystem includes npm, tooling for transpiling and bundling, and popular libraries and frameworks such as React, Angular, and Vue; TypeScript adds static typing on top of JavaScript.