JavaScript (often abbreviated as JS) is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. Over 97% of websites use it client-side for web page behavior, often incorporating third-party libraries.
Core Features
JavaScript is a high-level, often just-in-time compiled language that conforms to the ECMAScript standard.
- Dynamic Typing: You don’t need to specify data types for variables; the engine figures it out at runtime.
- Prototype-based Object-orientation: Unlike class-based languages (like Java), JS uses prototypes for inheritance.
- First-class Functions: Functions are treated like any other variable (can be passed as arguments, returned by other functions).
Modern JavaScript (ES6+)
Modern JS development often involves features introduced in ECMAScript 2015 (ES6) and later:
- Arrow Functions: A shorter syntax for writing function expressions.
- Promises & Async/Await: Syntactic sugar for handling asynchronous operations cleanly.
- Modules: Utilizing
importandexportto manage code structure.