JavaScript

JavaScript (JS) is a programming language and core technology of the Web, alongside HTML and CSS. It was created by Brendan Eich in 1995. As of 2025, the overwhelming majority of websites (98.9%) uses JavaScript for client side webpage behavior.

AI overview

JavaScript is a programming language that powers interactive features on nearly all websites today, making it one of the most essential technologies for how the internet works. It was created by Brendan Eich in 1995 and remains fundamental to web development alongside HTML and CSS, with 98.9% of websites currently using it.

AI-generated from the Wikipedia summary — may contain errors.

Key facts

Programming language.name: JavaScript
Programming language.screenshot: JavaScript code.png
Programming language.screenshot caption: Screenshot of JavaScript source code
Programming language.paradigms: Multi-paradigm: event-driven, functional, imperative, procedural, object-oriented
Programming language.memory management: Garbage collected
Programming language.family: ECMAScript
Programming language.designers: Brendan Eich of Netscape first; then others contributed to ECMAScript standard
Programming language.typing: Dynamic, weak, duck
Programming language.scope: lexical
Programming language.file extensions: .js • .mjs • .cjs
Programming language.implementations: V8, JavaScriptCore, SpiderMonkey;Chakra (deprecated)
Programming language.influenced by: Java, Scheme, Self, AWK, HyperTalk
Programming language.influenced: ActionScript, ArkTS, AssemblyScript, CoffeeScript, Dart, Haxe, JS++, Opa, TypeScript
Programming language.wikibooks: JavaScript

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Official website

ecma-international.org →

Link to the official site · not written by Vinony

Described at

tapor.ca →

Link to a page describing this subject · not written by Vinony

Wikidata facts

Instance of: event-driven programming
Named after: Java
Owned by: Oracle Corporation
Based on: ECMAScript
Designed by: Brendan Eich
Official website: www.ecma-international.org/publications-and-standards/standards/ecma-262
Image: JavaScript code.png
Said to be same as: JScript
Has use: computer programming

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Stack Exchange tag: stackoverflow.com/tags/javascript
influenced by: Python
Commons category: JavaScript
topic's main category: Category:JavaScript
media type: text/x-javascript
programming paradigm: imperative programming
inception: 1995-12-04
software version identifier: ECMAScript 2025
file extension: js
topic has template: Template:JavaScript
typing discipline: prototype-based programming
regulated by: Ecma International
publication date: 1995-09-00
announcement date: 1995-12-04
native label: JavaScript
hashtag: Javascript
on focus list of Wikimedia project: Wikipedia:Vital articles/Level/4
described at URL: consumerrights.wiki/w/JavaScript

Sources (15)

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~36 min read

Encyclopedic overview

57 sections

Contents

History
Creation at Netscape
Adoption by Microsoft
The rise of JScript
Growth and standardization
Reaching maturity
Trademark
Website client-side usage
Examples of scripted behavior
Libraries and frameworks
Other usage{{anchor|Server-side_JavaScript|Uses_outside_web_pages}}
Execution
JavaScript engine
Runtime system
Features
Imperative and structured
Weakly typed
Dynamic
Typing
Run-time evaluation
Object-orientation (prototype-based)
Prototypes
Functions as object constructors
Functions as methods
Functional
Lexical closure
Anonymous function
Delegative
Functions as roles (Traits and Mixins)
Object composition and inheritance
Miscellaneous
Zero-based numbering
Variadic functions
Array and object literals
Regular expressions
Promises
Async/await
Vendor-specific extensions
Syntax
Security
Cross-site scripting
Cross-site request forgery
Misplaced trust in the client
Misplaced trust in developers
Browser and plugin coding errors
Sandbox implementation errors
Hardware vulnerabilities
Development tools
Related technologies
Java
JSON
Transpilers
WebAssembly
Notes
References
Further reading
External links

Web browsers have a dedicated JavaScript engine that executes the client code. These engines are also utilized in some servers and a variety of apps. The most popular runtime system for non-browser usage is Node.js.

Excerpted from Wikipedia’s “JavaScript” article, available under the CC BY-SA 4.0 licence.

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