Spidermonkey
Spidermonkey is the JavaScript engine developed by Mozilla, originally created for the Netscape Navigator browser and now used in Firefox and other Mozilla projects. It interprets and executes JavaScript code, providing the runtime environment for web applications and server-side scripts. As an open-source engine, it implements the ECMAScript standard and includes features like just-in-time (JIT) compilation for performance optimization.
Developers should learn Spidermonkey when working on Mozilla-based projects, such as Firefox extensions, or when needing a standalone JavaScript engine for embedded systems, server-side scripting, or testing JavaScript code outside a browser. It's particularly useful for scenarios requiring high-performance JavaScript execution, such as in game engines or IoT devices, and for contributing to open-source browser development.