← Back to ProjectsView Architecture
View Demo
GitHub

QR Code Generator Project#

Project Overview##

This is a single-page web application that generates QR codes for different types of content. The application is built as a standalone HTML file containing embedded CSS and JavaScript, requiring no server-side processing or external frameworks beyond the specified CDN dependencies.

File Structure and Dependencies##

Core File###

  • index.html: Single HTML document containing the complete application (HTML structure, CSS styling, and JavaScript functionality)

External Dependencies###

  • Tailwind CSS: Loaded from cdn.tailwindcss.com for utility-first styling
  • QRious Library: Version 4.0.2 from cdnjs.cloudflare.com for QR code generation
  • Fallback QR Service: Uses api.qrserver.com as backup QR generation service

Application Architecture##

Three Primary Modes###

  1. URL Mode: Generates QR codes for website URLs with automatic protocol handling
  2. Text Mode: Creates QR codes for plain text content
  3. Contact Mode: Generates vCard-formatted QR codes for contact information

Technical Stack###

  • Pure HTML5, CSS3, and vanilla JavaScript
  • No build process or compilation required
  • Client-side only implementation
  • Progressive enhancement approach with fallbacks

User Interface Components##

Header Section###

  • Application title with gradient text styling
  • Icon container with QR code SVG symbol
  • Descriptive subtitle explaining functionality

Tab Navigation System###

  • Three-tab interface for switching between modes
  • Visual active/inactive state management
  • Accessible button implementation with SVG icons

Input Forms###

URL Form

  • Single URL input field with validation
  • Automatic HTTPS protocol addition for incomplete URLs
  • Placeholder text guidance
  • Real-time input processing

Text Form

  • Multi-line textarea for free-form text input
  • Responsive height adjustment
  • Character limit handling through QR code library constraints

Contact Form

  • Six-field contact information form:
    • First Name (text input)
    • Last Name (text input)
    • Phone Number (tel input)
    • Email Address (email input)
    • Organization (text input)
    • Website (url input)
  • Grid layout for optimal space utilization
  • vCard 3.0 format generation

QR Code Display Area###

  • Central display container with responsive sizing
  • Empty state with instructional messaging
  • Generated QR code presentation with styling
  • Action buttons for download and data copying
  • Data preview section showing encoded content

Styling and Design System##

Design Philosophy###

  • Modern, clean interface with gradient accents
  • Mobile-first responsive design
  • Glass-morphism and shadow effects
  • Purple-to-blue gradient theme throughout

CSS Architecture###

  • Embedded CSS with Tailwind integration
  • Custom CSS properties for consistent theming
  • Responsive breakpoints at 1024px (lg)
  • Fallback styles for CDN failure scenarios

Color Scheme###

  • Primary gradient: Purple (rgb(147, 51, 234)) to Blue (rgb(37, 99, 235))
  • Background: Multi-stop gradient from light purple to light blue
  • Text: Various shades of gray for hierarchy
  • Interactive states: Hover and focus treatments

Layout System###

  • CSS Grid for main content areas
  • Flexbox for component-level layouts
  • Maximum width container (64rem) with auto-centering
  • Consistent spacing using rem units

JavaScript Functionality##

State Management###

  • activeTab: Tracks current mode (url/text/contact)
  • qrData: Stores current encoded data string
  • qrCanvas: Reference to QRious canvas element

Event Handling###

  • Tab switching with visual state updates
  • Real-time input processing and QR generation
  • Clear functionality for all form fields
  • Download and clipboard operations

QR Code Generation Process###

Primary Method (QRious Library)

  • Canvas-based QR code creation
  • 300x300 pixel default size
  • Error correction level 'M'
  • White background, black foreground
  • Responsive canvas styling

Fallback Method (External API)

  • Image-based QR code from qrserver.com
  • URL encoding for special characters
  • Same visual styling as canvas method
  • Automatic fallback on library failure

Data Processing###

URL Handling

  • Automatic protocol detection and addition
  • HTTPS default for incomplete URLs
  • Trim whitespace processing
  • Empty input validation

Text Processing

  • Direct string encoding to QR code
  • Whitespace preservation
  • Unicode character support

vCard Generation

  • vCard 3.0 specification compliance
  • Structured contact data formatting
  • Optional field handling
  • Proper line break formatting

User Interface Logic###

Tab Management

  • CSS class manipulation for active states
  • Section visibility toggling
  • Dynamic title updates
  • Input field focus management

QR Display States

  • Empty state with instructional content
  • Generated state with QR code and controls
  • Error state handling with fallback options

Action Button Functionality

  • PNG download with dynamic filename generation
  • Clipboard API integration with fallback
  • Visual feedback for user actions
  • Success/error state indicators

Browser Compatibility Features##

Modern Browser Support###

  • Canvas API for QR rendering
  • Clipboard API for copy functionality
  • CSS Grid and Flexbox layouts
  • Modern JavaScript (ES6+) features

Fallback Mechanisms###

  • External QR API for library failures
  • execCommand for clipboard on older browsers
  • CSS fallbacks for styling
  • Graceful degradation approach

Progressive Enhancement###

  • Core functionality works without JavaScript
  • Styling enhancement with CSS
  • Interactive features as JavaScript layer

Data Handling and Security##

Client-Side Processing###

  • No server-side data transmission
  • Local QR code generation
  • Privacy-focused approach
  • No data persistence or storage

Input Validation###

  • HTML5 input type validation
  • JavaScript sanitization for URLs
  • vCard format validation
  • Empty field handling

Error Handling###

  • Try-catch blocks for QR generation
  • Fallback service integration
  • User feedback for failed operations
  • Console logging for debugging

File Size and Performance##

Asset Loading###

  • External CDN dependencies for optimization
  • Lazy loading of QR generation
  • Efficient DOM manipulation
  • Minimal JavaScript bundle size

Runtime Performance###

  • Real-time QR generation without debouncing
  • Canvas reuse for memory efficiency
  • Event delegation for input handling
  • Optimized re-rendering patterns

Accessibility Features##

Semantic HTML###

  • Proper heading hierarchy
  • Form labeling and association
  • Button role definitions
  • Alt text for generated images

Keyboard Navigation###

  • Tab-accessible interface
  • Focus management
  • Keyboard event handling
  • Screen reader compatibility

Visual Accessibility###

  • High contrast text and backgrounds
  • Scalable vector icons
  • Responsive font sizing
  • Clear visual hierarchy

Code Organization##

HTML Structure###

  • Semantic sectioning elements
  • Accessible form structure
  • Progressive enhancement markup
  • SEO-friendly meta tags

CSS Organization###

  • Component-based styling
  • Media query organization
  • Custom property usage
  • Maintainable class naming

JavaScript Structure###

  • Modular function organization
  • Clear separation of concerns
  • Event-driven architecture
  • Consistent error handling patterns

This QR Code Generator represents a complete, production-ready web application that prioritizes user experience, accessibility, and cross-browser compatibility while maintaining a modern, responsive design.

Architecture Diagram

Drag to pan, scroll to zoom