Expand/Collapse Widget Demo

HTML (HyperText Markup Language) is the standard markup language for creating web pages. It provides the structure and content of websites by using a system of tags and elements.

Key features of HTML:

Semantic markup for structured content
Support for multimedia elements
Form controls for user interaction
Accessibility features for inclusive web design

CSS (Cascading Style Sheets) is used to style and layout web pages. It allows you to control colors, fonts, spacing, and positioning of elements on a page.

CSS can be applied in three ways:

Inline - directly in HTML elements
Internal - using <style> tags in the document head
External - linking to separate CSS files

JavaScript is a programming language that enables interactive web pages. It can update content, control multimedia, animate images, and much more.

This expand/collapse widget demonstrates:

DOM manipulation with classList
Event handling with onclick
CSS transitions for smooth animations
Toggle functionality for show/hide behavior

When building web applications, follow these best practices:

Use semantic HTML for better accessibility
Keep CSS organized and maintainable
Write clean, readable JavaScript code
Test your application across different browsers
Optimize images and assets for performance
Implement responsive design for mobile devices

Expand/Collapse Widgets

What is HTML?

Getting Started with CSS

JavaScript Basics

Best Practices