JavaScript engine

JavaScript engines are interpreters that parse and execute {{glossary("JavaScript")}} code. Modern JavaScript engines use just-in-time (JIT) compilation to convert JavaScript code into machine code that can be executed by a computer's processor. A JavaScript engine is typically developed and used in web {{glossary("browser", "browsers")}} to run client-side code but can also be used in server-side environments like {{glossary("Node.js")}}.

In a browser, the JavaScript engine operates together with the rendering engine via the {{glossary("DOM", "Document Object Model")}} and {{glossary("WebIDL", "Web IDL")}} bindings. Some JavaScript engines also execute {{glossary("WebAssembly")}} code in the same sandbox as regular JavaScript code.

Do not confuse JavaScript engines with {{glossary("engine/rendering", "rendering engines")}}, which are also crucial parts of browsers.

Common JavaScript engines include:

• V8
• SpiderMonkey
• JavaScriptCore

See also

• JavaScript engine on Wikipedia
• JavaScript implementations
• Related glossary terms:
  • {{glossary("Engine")}}
  • {{glossary("JavaScript")}}
  • {{glossary("WebAssembly")}}
  • {{glossary("Browser")}}
  • {{glossary("Node.js")}}