1.1 What is JavaScript?

JavaScript is a versatile and powerful programming language primarily used for building interactive web pages. It's an essential technology for front-end web development, working alongside HTML (for structure) and CSS (for styling).

The Language of the Web

Originally, JavaScript was designed to make web pages interactive. Think of features like animated graphics, interactive maps, form validations, and dynamic content updates—all of these are often powered by JavaScript.

Over time, its capabilities have expanded dramatically. With Node.js, JavaScript can now be used for back-end development, meaning you can build full-stack applications using a single language.

Where does it run?

Most commonly, JavaScript runs in your web browser. Every modern web browser has a JavaScript engine (like V8 in Chrome, SpiderMonkey in Firefox) that executes the JavaScript code.

Beyond the browser, JavaScript can also run on servers (Node.js), mobile devices (React Native, NativeScript), desktop applications (Electron), and even embedded systems.

Key Characteristics:

• High-level: Abstracts away complex details of the computer.
• Interpreted: Code is executed line by line by an interpreter, not pre-compiled.
• Multi-paradigm: Supports object-oriented, functional, and imperative programming styles.
• Dynamic: Types can change during runtime.
• Client-side & Server-side: Can be used for both front-end and back-end development.

Ready to dive deeper? Let's set up your development environment in the next lesson!