Interactive Timeline Overview

The Interactive Timeline creates a visually stunning scrolling experience that guides visitors through your process, history, or key milestones. It features a dynamic dot that follows user scroll position, alternating left-right layouts, customizable feature tags, and smooth animations, all while maintaining zero dependencies and working seamlessly across all modern browsers.

HTML Structure

The generated HTML structure consists of:

• A unique wrapper ID like timeline-scroll-abc123 for complete isolation
• Process container with display: flex; flex-direction: column for vertical layout
• Timeline element with position: absolute; left: 50% for center alignment
• Scrolling dot with position: absolute; transition: top 0.3s ease-out
• Process steps with data-step attributes for identification
• Self-contained JavaScript wrapped in DOMContentLoaded listener

Timeline Animation System

The scrolling dot follows viewport position with intelligent tracking:

• Initial position calculated using getBoundingClientRect() on first element
• Dot positioning: width: 32px; height: 32px; border-radius: 50%
• Transform centering: transform: translateX(-50%) for precise alignment
• Z-index hierarchy: z-index: 3 above timeline line
• Viewport detection: window.innerHeight/2 for center tracking
• Active state management with .active class toggling

Step Layout System

Alternating zigzag pattern creates visual interest:

• Odd steps: flex-direction: row with content left, image right
• Even steps: flex-direction: row-reverse for alternation
• Content margins: margin-right: 10% and margin-left: 10%
• Image sizing: width: 40%; height: 300px; object-fit: cover
• Flexbox alignment: align-items: center; justify-content: space-between
• Position relative on steps for number positioning

Number Typography

Large background numbers create depth and hierarchy:

• Absolute positioning: position: absolute; z-index: 0
• Font sizing customizable from 100px to 400px
• Opacity control: rgba(r, g, b, opacity) with variable transparency
• Positioning logic: top: -fontSize * 0.25px for proportional offset
• Weight emphasis: font-weight: 700 for bold impact
• Active state boost: opacity * 2 capped at 0.5 maximum

Feature Tags Implementation

Interactive tags highlight key features with hover effects:

• Container: display: flex; flex-wrap: wrap; gap: 15px
• Tag styling: padding: 12px 20px; border-radius: 6px
• Background with transparency: rgba(r, g, b, 0.2) for subtlety
• Hover transition: transition: all 0.3s ease
• Full opacity on hover: background-color: solid color
• Font weight: font-weight: 500 for readability

Scroll Detection Algorithm

Intelligent viewport tracking for smooth dot movement:

• Container bounds check: containerTop > window.innerHeight
• Distance calculation: Math.abs(stepCenter - window.innerHeight/2)
• Closest element detection using closestDistance comparison
• Active class management: classList.remove('active') then add
• Number element fallback: querySelector('.process-number') || step
• Dot position update: timelineDot.style.top = dotPosition + 'px'

Responsive Breakpoints

Mobile-first design ensures perfect display on all devices:

• Tablet breakpoint: @media (max-width: 992px)
• Container padding: padding: 0 6% for edge spacing
• Vertical stacking: flex-direction: column on all steps
• Timeline repositioning: left: 30px; transform: none
• Mobile breakpoint: @media (max-width: 576px)
• Proportional scaling: font sizes at 0.75x on mobile

CSS Architecture

Scoped styling prevents conflicts with existing styles:

• ID-prefixed selectors: #timeline-scroll-abc123 .process-step
• Font inheritance: font-family: inherit throughout
• Color important flags: color: #fff !important for titles
• Z-index hierarchy: 0 numbers, 1 timeline, 2 content, 3 dot
• Box model consistency: box-sizing: border-box implicit
• Transition performance: transform-only for GPU acceleration

Event Handling System

Optimized scroll performance with smart updates:

• Scroll listener: window.addEventListener('scroll', updateDotPosition)
• Resize handler: window.addEventListener('resize', updateDotPosition)
• Initial positioning on load ensures correct start state
• No throttling needed due to CSS transition smoothing
• Passive listeners compatible for better scroll performance
• Container visibility check prevents unnecessary calculations

Color System Flexibility

Complete color customization with intelligent defaults:

• Background support: any color including #ffffff default
• Timeline/dot color synchronized for cohesion
• Number color with separate opacity control
• Text color inheritance from parent or custom
• Feature tag dual colors: background and text
• RGB conversion: hexToRgb() for rgba support

Typography Controls

Flexible text hierarchy with semantic HTML:

• Heading levels: h1 through h6 selectable
• Title sizing: 24px to 72px range
• Description text: font-size: 18px; line-height: 1.6
• Opacity on descriptions: opacity: 0.9 for hierarchy
• Mobile scaling maintains readability
• Font family inheritance preserves brand consistency

Image Handling

Responsive images with consistent aspect ratios:

• Container constraint: max-width: 40% on desktop
• Fixed height: height: 300px prevents layout shift
• Object fit: object-fit: cover maintains proportions
• Border radius: border-radius: 10px for modern look
• Alt text support for accessibility
• Mobile height reduction: height: 200px on small screens

Performance Optimization

Lightweight implementation prioritizes speed:

• Zero external dependencies - vanilla JavaScript only
• Single reflow on initialization
• Transform-only animations avoid repaints
• No jQuery or framework overhead
• Efficient querySelector usage with caching
• Event delegation where applicable
• Total size under 12KB uncompressed

Accessibility Features

Built-in accessibility ensures inclusive design:

• Semantic HTML structure with proper headings
• Image alt attributes for screen readers
• Color contrast meeting WCAG standards
• Keyboard navigation compatible
• Focus states on interactive elements
• Logical content flow for assistive technology

Implementation Benefits

This solution provides significant advantages:

• Works immediately without initialization code
• Compatible with Duda, WordPress, Wix, and all page builders
• No conflicts with existing JavaScript libraries
• SEO-friendly with proper semantic markup
• Supports unlimited timeline steps
• Customizable without code knowledge via builder tool
• Mobile-first responsive design built in
• Future-proof with standard web APIs
• Copy-paste implementation in seconds
• Maintains functionality with slow connections