Introduction to JavaScript

Brendan Eich created JavaScript at Netscape in 1995. ECMAScript standardizes the language, while engines such as V8, SpiderMonkey, and JavaScriptCore implement it. Browsers add the DOM and Web APIs; Node.js supplies server and operating-system APIs. These hosts are separate from the language itself.

One language, many environments

const message = "Hello, JavaScript";
console.log(message);

JavaScript is dynamically typed, garbage-collected, prototype-based, multi-paradigm, and event-driven. Engines interpret and JIT-compile code. On the web it controls behavior, data fetching, accessibility interactions, and application state alongside HTML and CSS. The same language also powers servers, command-line tools, desktop shells, testing, and build systems. Portability still depends on host APIs and supported ECMAScript versions.