JavaScript (/ˈdʒɑːvəˌskrɪpt/[5]) is a high-level, dynamic, untyped, and interpreted programming language. [6] It has been standardized in the ECMAScript language specification.[7] Alongside HTML and CSS, it is one of the three core technologies of World Wide Web content production; the majority of websites employ it and it is supported by all modern Web browsers without plug-ins.[6] JavaScript is prototype-based with first-class functions, making it a multi-paradigm language, supporting object-oriented,[8] imperative, and functional programming styles.[6] It has an API for working with text, arrays, dates and regular expressions, but does not include any I/O, such as networking, storage, or graphics facilities, relying for these upon the host environment in which it is embedded.[7]

JavaScript was influenced by programming languages such as Self and Scheme.[9] JavaScript is also used in environments that are not Web-based, such as PDF documents, site-specific browsers, and desktop widgets. Newer and faster JavaScript virtual machines (VMs) and platforms built upon them have also increased the popularity of JavaScript for server-side Web applications. On the client side, JavaScript has been traditionally implemented as an interpreted language, but more recent browsers perform just-in-time compilation. It is also used in game development, the creation of desktop and mobile applications, and server-side network programming with run-time environments such as Node.js.