JavaScript is a popular programming language known for its lightweight and interpreted or just-in-time compiled features. It also has first-class functions, making it highly versatile. Although commonly used for scripting web pages, it has gained prominence in various non-browser environments like Node.js, Apache CouchDB, and Adobe Acrobat.
As a programming language, JavaScript is responsible for adding interactivity to websites. The JavaScript engine is a single-threaded language that utilizes a callback queue.
For more information, visit the Mozilla Developer Network at https://developer.mozilla.org/en-US/docs/Web/JavaScript.