The first

engines An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

for

JavaScript JavaScript (), often abbreviated as JS, is a programming language and core technology of the World Wide Web, alongside HTML and CSS. Ninety-nine percent of websites use JavaScript on the client side for webpage behavior. Web browsers have ...

were mere

interpreter Interpreting is translation from a spoken or signed language into another language, usually in real time to facilitate live communication. It is distinguished from the translation of a written text, which can be more deliberative and make use o ...

s of the

source code In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer. Since a computer, at base, only ...

, but all relevant modern engines use

just-in-time compilation In computing, just-in-time (JIT) compilation (also dynamic translation or run-time compilations) is compilation (of computer code) during execution of a program (at run time) rather than before execution. This may consist of source code transl ...

for improved performance. JavaScript engines are typically developed by

web browser A web browser, often shortened to browser, is an application for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's scr ...

vendors, and every major browser has one. In a browser, the JavaScript engine runs in concert with the rendering engine via the

Document Object Model The Document Object Model (DOM) is a cros s-platform and language-independent API that treats an HTML or XML document as a tree structure wherein each node is an object representing a part of the document. The DOM represents a document with ...

and

Web IDL Web IDL is an interface description language (IDL) format for describing APIs (application programming interfaces) that are intended to be implemented in web browsers. Its adoption was motivated by the desire to improve the interoperability of ...

bindings. However, the use of JavaScript engines is not limited to browsers; for example, the

V8 engine A V8 engine is an eight- cylinder piston engine in which two banks of four cylinders share a common crankshaft and are arranged in a V configuration. Origins The first known V8 was the Antoinette, designed by Léon Levavasseur, a ...

is a core component of the Node.js

runtime system In computer programming, a runtime system or runtime environment is a sub-system that exists in the computer where a program is created, as well as in the computers where the program is intended to be run. The name comes from the compile time ...

. They are also called

ECMAScript ECMAScript (; ES) is a standard for scripting languages, including JavaScript, JScript, and ActionScript. It is best known as a JavaScript standard intended to ensure the interoperability of web pages across different web browsers. It is stan ...

engines, after the official name of the specification. With the advent of

WebAssembly WebAssembly (Wasm) defines a portable binary-code format and a corresponding text format for executable programs as well as software interfaces for facilitating communication between such programs and their host environment. The main goal of ...

, some engines can also execute this code in the same

sandbox A sandbox is a sandpit, a wide, shallow playground construction to hold sand, often made of wood or plastic. Sandbox or sand box may also refer to: Arts, entertainment, and media * Sandbox (band), a Canadian rock music group * Sandbox (Gu ...

as regular JavaScript code.

History

The first JavaScript engine was created by

Brendan Eich Brendan Eich ( ; born July 4, 1961) is an American computer programmer and technology executive. He created the JavaScript programming language and co-founded the Mozilla project, the Mozilla Foundation, and the Mozilla Corporation. He serve ...

in 1995 for the

Netscape Navigator The 1990s releases of the Netscape (web browser), Netscape line referred to as Netscape Navigator were a series of now discontinued web browsers. from versions 1 to 4.08. It was the Core product, flagship product of the Netscape, Netscape Comm ...

. It was a rudimentary

for the nascent language Eich invented. (This evolved into the

SpiderMonkey SpiderMonkey is an open-source JavaScript and WebAssembly engine by the Mozilla Foundation. The engine powers the Firefox Web browser and has used multiple generations of JavaScript just-in-time (JIT) compilers, including TraceMonkey, Jäg ...

engine, still used by the

Firefox Mozilla Firefox, or simply Firefox, is a free and open-source web browser developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. It uses the Gecko rendering engine to display web pages, which implements curr ...

browser.)

Google Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial ...

debuted its Chrome browser in 2008, with the V8 JavaScript engine that was faster than its competition. The key innovation was

(JIT), which

Mozilla Mozilla is a free software community founded in 1998 by members of Netscape. The Mozilla community uses, develops, publishes and supports Mozilla products, thereby promoting free software and open standards. The community is supported institution ...

had also been working on for SpiderMonkey. Because of V8's performance, the other browser vendors needed to overhaul their engines for JIT.

Apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

developed the

Nitro Nitro may refer to: Chemistry *Nitrogen, a chemical element and a gas except at very low temperatures, with which many compounds are formed: **Nitro compound, an organic compound containing one or more nitro functional groups, -NO2 **Nitro ligand ...

engine for its

Safari A safari (; originally ) is an overland journey to observe wildlife, wild animals, especially in East Africa. The so-called big five game, "Big Five" game animals of Africa – lion, African leopard, leopard, rhinoceros, African elephant, elep ...

browser, which had 30% better performance than its predecessor.Safari 5 Released
/ref> Mozilla then leveraged portions of Nitro to improve SpiderMonkey. Since 2017, these engines have added support for

List

References

{{DEFAULTSORT:JavaScript engine