JavaScript is a high-level, interpreted programming language that powers interactivity on the web. Created by Brendan Eich in 10 days, it became the universal language of web browsers and later expanded to servers, mobile apps, and beyond.
Origins
Netscape hired Brendan Eich in 1995 to create a scripting language for Navigator, their web browser. Originally called Mocha, then LiveScript, it was renamed JavaScript as a marketing strategy to capitalize on Java’s popularity—despite having little relation to Java.
Key Features
JavaScript introduced accessible programming to millions:
- First-class functions: Functions as values, enabling functional programming
- Prototype-based objects: Flexible object system without classes
- Dynamic typing: Variables can hold any type
- Event-driven: Responds to user actions and asynchronous events
- Closures: Functions remember their creation environment
Evolution
JavaScript transformed dramatically:
- ECMAScript standardization: ECMA-262 provided cross-browser consistency
- ES6/ES2015: Major modernization with classes, modules, arrows
- Node.js: JavaScript on servers
- TypeScript: Static typing layer
Impact
JavaScript became unavoidable:
- Only language that runs natively in browsers
- Powers virtually all web interactivity
- Node.js made it a server language
- React Native, Electron extended it to mobile and desktop
- Most used programming language by many measures