What is JavaScript and what is its official standard?
JavaScript is the programming language that makes web pages interactive; its official standard is ECMAScript (ECMA-262).
JavaScript was created at Netscape in 1996 to bring life to otherwise static HTML pages — letting them react to the user instead of just sitting there. Because so many browser vendors implemented it, the language was standardised so that everyone's version behaves the same way. That standard is ECMA-262, and the language it defines is called ECMAScript. In everyday speech people say "JavaScript"; the formal spec is "ECMAScript" (which is why language versions are named ES2015, ES2020, and so on).
Typical jobs people use JavaScript for:
- Reacting to user input — clicks, key presses, mouse movement
- Validating form values before they are submitted
- Dynamic HTML: changing the page's content and structure on the fly (DOM manipulation)
- Single-Page Applications, where the browser itself acts as the whole app's GUI
- Multimedia and graphics — video, audio, visual effects
A common gotcha: despite the name, JavaScript has nothing to do with Java. The name was a 1990s marketing decision to ride on Java's popularity; the two are unrelated languages.
Go deeper:
JavaScript (Wikipedia) — history, the Ecma TC39 committee, and how the language relates to the wider web platform.