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JavaScript Engine and Basics

Target Version: ECMAScript 2023+ (ES14+) Official Documentation: MDN JavaScript Guide

1. Introduction to JavaScript​

An essential language for modern web development. Created in 10 days by Brendan Eich in 1995, it has expanded from the client (browser) to the server (Node.js) domain.

  • Features: First-class functions, prototype-based inheritance, single-threaded asynchronous processing.
  • Advantages: Runs in all browsers and has the world's most active community (npm).
  • Core Engines: Chrome's V8, Firefox's SpiderMonkey, Safari's JavaScriptCore.

2. Hello, World! (Console Learning)​

Try running this directly in your browser's developer tools (F12) Console tab.

// Modern variable declaration (const, let recommended)
const message = "Hello, JavaScript!";
console.log(message);

// Arrow Function
const multiply = (a, b) => a * b;
console.log(`10 * 20 = ${multiply(10, 20)}`);

3. Core Basic Syntax​

  • Variable Declaration: const (immutable), let (mutable, block-scoped).
  • Data Types: Number, String, Boolean, Object, undefined, null.
  • Asynchronous Processing: Promise-based logic processing via async / await.
  • Module Systems: ESM (import / export), CommonJS (require).