Introduction to JavaScript
Welcome to the comprehensive JavaScript tutorial! JavaScript (JS) is a lightweight, interpreted, or just-in-time compiled programming language with first-class functions. While it is most well-known as the scripting language for Web pages, many non-browser environments also use it, such as Node.js, Apache CouchDB and Adobe Acrobat.
What is JavaScript?
JavaScript is one of the three core technologies of the World Wide Web, alongside HTML and CSS. It enables interactive web pages and is an essential part of web applications. The vast majority of websites use JavaScript for client-side page behavior, and it is increasingly used for server-side development with Node.js.
Client-side vs. Server-side JavaScript
- **Client-side JavaScript:** Runs in the user's web browser. It is used to make web pages interactive, validate forms, create animations, handle user events, and communicate with servers (e.g., via AJAX).
- **Server-side JavaScript (Node.js):** Runs on a web server. It allows developers to build entire web applications using JavaScript for both the front-end and back-end, handle database operations, and manage server logic.
Setting Up Your Development Environment
You can start writing and running JavaScript code almost immediately.
- **Browser Console:** For client-side JavaScript, you can open your web browser's developer console (usually by pressing F12 or Ctrl+Shift+I / Cmd+Option+I). Navigate to the "Console" tab to write and execute JavaScript directly.
- **HTML File:** You can embed JavaScript directly within an HTML file using `