JavaScript
JavaScript
JavaScript (often abbreviated as JS) is a high-level, interpreted programming language that conforms to the ECMAScript specification. It is one of the core technologies of the World Wide Web, alongside HTML and CSS. JavaScript enables interactive web pages and is an essential part of web application development. The majority of websites employ it for client-side behavior, and all major web browsers have a dedicated JavaScript engine to execute it.
JavaScript is a prototype-based, multi-paradigm language, supporting object-oriented, imperative, and functional programming styles. It has an API for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM).
History
JavaScript was created by Brendan Eich in 1995 while he was at Netscape Communications Corporation. Initially named Mocha, then LiveScript, it was finally renamed JavaScript to capitalize on the popularity of Java. The first version appeared in Netscape Navigator 2.0 in 1995.
In 1996, Netscape submitted JavaScript to Ecma International for standardization, leading to the first edition of the ECMAScript specification in 1997. Subsequent editions have added features such as class syntax, arrow functions, modules, and asynchronous programming with Promises and async/await.
Features
- Dynamic typing – Variables do not require a declared type; type is determined at runtime.
- First-class functions – Functions can be assigned to variables, passed as arguments, and returned from other functions.
- Prototype-based inheritance – Objects inherit properties and methods from other objects.
- Event-driven programming – Commonly used for handling user interactions and asynchronous events.
- Cross-platform – Runs in any browser with a JavaScript engine; also used on servers (e.g., Node.js) and in desktop/mobile applications.
Modern Usage
JavaScript has expanded beyond the browser. Node.js allows server-side scripting, while frameworks such as React, Angular, and Vue.js are widely used for building single-page applications. The npm package manager provides a vast ecosystem of libraries and tools. JavaScript is also used in Internet of Things (IoT) devices, game development, and desktop applications via frameworks like Electron.