JavaScript Basics

JavaScript is the main programming language that brings interactivity and logic to websites. While HTML defines the structure of a page and CSS styles it, JavaScript allows you to dynamically change content, respond to user input, and communicate with external data sources.

JavaScript works closely with other languages and technologies:

• HTML – JavaScript can create, remove, or modify HTML elements dynamically using the DOM (Document Object Model).
• CSS – JavaScript can apply, remove, or switch CSS classes and styles, allowing dynamic design changes like animations, themes, or responsive layouts.
• Back-end Languages – JavaScript can send and receive data via APIs (using fetch() or AJAX) to work with back-end systems built in Python, Java, Node.js, PHP, etc.
• Databases – Through APIs or back-end code, JavaScript interacts with SQL or NoSQL databases to store and retrieve information.
• Frameworks & Libraries – JavaScript powers popular frameworks like React, Angular, Vue, and server-side environments like Node.js.

In short: HTML provides the content, CSS provides the design, and JavaScript provides the brain.