JavaScriptEngine

A JavaScript engine is a computer program that directly executes JavaScript code. It is also known as a JavaScript interpreter or a JavaScript implementation. JavaScript engines are typically embedded within web browsers, but they can also be found in other applications such as Node.js, which allows JavaScript to be run on servers. The primary function of a JavaScript engine is to parse and execute JavaScript code, translating it into machine code that the computer's processor can understand and run.

Modern JavaScript engines employ sophisticated techniques to optimize code execution. This often involves a combination of interpretation and just-in-time (JIT) compilation. Initially, the code may be interpreted, but frequently executed sections are compiled into highly optimized machine code during runtime. This JIT compilation significantly boosts performance by reducing the overhead associated with interpretation. Popular examples of JavaScript engines include V8 (used in Chrome and Node.js), SpiderMonkey (used in Firefox), and JavaScriptCore (used in Safari). These engines are constantly evolving to improve speed, efficiency, and adherence to JavaScript standards.