What JavaScript is and what it enables

Summary

JavaScript is a cross-platform, object-oriented scripting language used to make webpages interactive, enabling features like animations, clickable buttons, and popup menus. It runs inside a host environment (most commonly a web browser) and can be connected to objects in that environment to provide programmatic control—such as modifying the Document Object Model (DOM) and responding to user events (mouse clicks, form input, navigation). JavaScript also has server-side variants such as Node.js, which allow websites to do more than serve static files, including tasks like realtime collaboration and handling custom requests from browser code. JavaScript is standardized through ECMAScript, an open specification maintained by Ecma International (ECMA-262, also approved by ISO). The ECMAScript specification defines how the language should work, while the DOM is standardized separately by W3C/WHATWG. For learning and writing code, JavaScript documentation is intended for programmers, whereas the ECMAScript specification is primarily for implementers of standards-compliant engines. To get started, you only need a modern web browser and its JavaScript console, which lets you run JavaScript directly on the current page for quick experimentation.

Key Points

• 1

  JavaScript makes webpages interactive by controlling browser objects like the DOM and responding to user events.

• 2

  JavaScript can also run on servers (e.g., Node.js) to add functionality such as realtime collaboration and custom request handling.

• 3

  JavaScript behavior is standardized by ECMAScript (ECMA-262/ISO-16262), while the DOM is standardized separately by W3C/WHATWG.

• 4

  You can begin learning by using a browser’s JavaScript console to execute code and experiment quickly.