Scrolling through web pages, CSS animations on scroll transform static websites into dynamic experiences. The modern web design landscape demands interactivity, and these scroll-triggered animations have become essential for creating engaging user interfaces. Using Intersection Observer API and proper animation timing functions, developers can craft experiences that respond naturally to user interaction.
Why should you care?
These animations significantly boost UX improvements:
- Increased engagement metrics (lowering bounce rates)
- Improved Core Web Vitals when properly optimized
- Enhanced visual storytelling capabilities
- Better accessibility (when implemented with standards in mind)
Whether you’re deep into front-end development or just starting with CSS3 capabilities, mastering these techniques elevates your projects beyond static displays.
You’ll discover how to implement scroll-based transitions through keyframe animations, enhance viewport-based animations, and explore real-world applications that drive conversion.
By the end, you’ll have practical knowledge of implementing scroll-activated effects that work across browsers. We’ll examine how tools like GSAP ScrollTrigger and AOS Library can transform ordinary sites into interactive experiences, meeting the demands of truly modern website design while maintaining performance.
Without proper implementation, however, these animations can harm your web performance metrics and create accessibility issues. We’ll cover best practices for balancing visual impact with technical excellence.
Creative Portfolio Website Slider
Scrolling animations don’t need to be built from scratch. Animation libraries like GSAP offer pre-built solutions that balance performance with visual impact. The Creative Portfolio Website template demonstrates how scroll-triggered animations can showcase work professionally while maintaining strong Core Web Vitals.
This one-page portfolio uses scroll-activated effects that work across all devices, thanks to proper mobile responsiveness implementation. The animations serve a purpose: highlighting projects progressively as users scroll, creating a natural visual hierarchy.
Woodworking Website Template
Single-page applications benefit tremendously from thoughtful CSS animation on scroll implementation. This template demonstrates how craft-focused businesses can create an immersive web experience without sacrificing performance.
The template uses scroll event handling to trigger subtle wood-grain animations that enhance the theme without distracting from content. This technique uses animation easing functions that mimic natural materials.
Architecture Website Template
Architecture firms need precise, structured websites. This template uses parallax effect and scroll-based transitions to create depth while maintaining clean lines.
The template integrates ScrollTrigger functionality that responds to viewport position, creating a sense of 3D space on a 2D screen. For architecture firms, this spatial awareness connects directly to their brand values.
Food Delivery Lottie Scroll
Lottie animations represent a powerful approach to scroll-triggered effects that balance file size with visual complexity. This template shows how food delivery services can use animation to explain their process.
The scroll-linked animations explain the delivery journey step-by-step, improving user understanding through visual storytelling. This directly addresses user questions about how the service works.
Design DNA Scroll Video
Video content typically consumes significant bandwidth. This template demonstrates how scroll-based navigation can make video consumption more interactive and efficient.
Story Blocks
Storytelling drives engagement, but long-form content often suffers from poor readability online. The Story Blocks template addresses this through progressive enhancement with CSS3 capabilities.
Corporate Website Template
Corporate sites must balance professionalism with engagement. This template demonstrates how subtle CSS transform properties can create movement that guides without distracting.
The responsive implementation ensures animations work across devices, addressing the challenge of maintaining consistent animation timing functions across varied screen sizes.
Scroll-activated progress bar
Author: Bogdan Sandu from WPDean and Design Your Way
Progress indicators provide crucial user feedback during navigation. This implementation by Bogdan Sandu shows how a simple scroll event listener can create an intuitive reading progress bar.
This technique improves user experience enhancement by:
- Providing constant spatial awareness within long content
- Creating visual feedback that responds to user actions
- Establishing a sense of progress and achievement
When paired with proper animation performance metrics monitoring, these small UI enhancements significantly improve engagement without performance penalties.
Entrance animation
Author: AndreasSikjaer
This example by AndreasSikjaer demonstrates proper viewport calculations for triggering animations only when elements enter the screen.
A pen by Mais
Author: Mais
This implementation demonstrates CSS animation keyframes with four-way control options, allowing directional animations based on scroll behavior.
The animation applies natural physics principles to movement, with acceleration and deceleration that feels intuitive to users. This attention to animation easing functions creates a sense of quality that static interfaces lack.
Trigger a CSS animation on the scroll
Author: MrJohnson
This example by MrJohnson demonstrates text-based animations with minimal animation delay, creating a clean, sequential reveal effect.
The implementation uses staggered timing to create hierarchy, drawing attention first to headings, then to supporting content. This technique supports natural reading patterns and information processing.
Visual hierarchy reinforcement through animation timing helps users understand content relationships without requiring explicit visual cues like arrows or lines.
CSS Reveal Slider
Author: Adam Kuhn
Adam Kuhn’s implementation uses animation direction creatively, with sliding color overlays that gradually reveal images.
This technique creates anticipation and draws attention to key visual elements through controlled timing. The staggered reveal forces users to notice each element individually rather than skimming past important content.
ScrollifyJS + AnimateCSS + Flexbox
Author: Zeindelf
This tool by Zeindelf demonstrates how combining multiple animation libraries can create complex experiences while maintaining code maintainability.
CSS Scroll Reveal Sections
Author: Ryan Mulligan
Ryan Mulligan’s implementation uses clip-path properties to create hero sections with fixed positions, demonstrating advanced masking techniques that create depth without using resource-intensive 3D transforms.
CSS scroll-behavior, scroll-snap-type & mix-blend-mode
Author: Andrej Sharapov
Andrej Sharapov demonstrates how native CSS properties can create complex scroll-based transitions without JavaScript, improving performance and reducing dependency chains.
Screen scroll effect
Author: tejasprithvi
Tejasprithvi’s implementation demonstrates responsive scroll animations that work consistently across devices, addressing the challenge of creating reliable animations for varying screen sizes.
3D CSS Scroll
Author: Shaw
Shaw demonstrates a simple yet eye-catching scroll effect with easily adjustable animation duration settings. The implementation creates depth through subtle parallax movements, creating an immersive experience without overwhelming users.
3D Ebook Flip Animation
Author: Saranya Mohan
Saranya Mohan’s flip-style animation demonstrates advanced CSS transform properties that create realistic page-turning effects. The implementation creates a tactile quality that connects digital interaction to familiar physical experiences.
Animated Info Card
Author: Adam Kuhn
Adam Kuhn’s navigable info card demonstrates how animations can replace traditional UI patterns while improving engagement. The almost purely CSS implementation achieves complex interactions without heavy JavaScript dependencies.
(WIP) Using: target for basic animation
Author: Glenn Philp
Glenn Philp demonstrates how the CSS :target selector can create simple scroll-activated effects without JavaScript, improving performance and reducing code complexity.
Skew Scrolling Effect
Author: Dronca Raul
Dronca Raul’s implementation demonstrates how animation direction can create interesting visual effects that respond dynamically to scroll behavior. The tilting lines create visual interest without distracting from content.
CSS only Scrolling shadow
Author: Temani Afif
Temani Afif demonstrates how simple CSS effects can significantly improve readability for text-heavy content. The scrolling shadow provides crucial visual feedback about content overflow, addressing a common usability challenge.
Reverse Cross
Author: Jason Skrzypek
Jason Skrzypek demonstrates colorful transitions with straightforward CSS implementation. The effect creates visual interest through color theory application, using complementary colors to create tension and resolution during scroll transitions.
Head for the Hills
Author: Adam Kuhn
This is a beautiful animation that changes a simple subscription bar into an animated scene. After placing an email address, selecting subscribe sends the letters running into the subscription box with a flourish. It’s a great example of taking a simple feature and making it interesting.
Codevember 4 :: Sky
Author: Magnificode
This animation provides you with a mountainous background that moves while you scroll. As you scroll, the picture will split into the text you want to display.
Overlapping horizontal slideshow using position: sticky;
Author: Håvard Brynjulfsen
A simple animation that displays a slideshow of images from left to right.
GSAP ScrollTrigger – Marquee Page Border
Author: Ryan Mulligan
An interesting animation tool that’s great for large amounts of text.
Endless Hallway
Author: Adam Kuhn
Another interesting animation that would act as a great loading screen. It is also animated somewhat jaggedly, which gives it a sketchbook feel.
Parallax scrolling effect
Author: Oleksandr H.
As you scroll through a page, this animation will draw images swiftly along with the connected text. With this effect, visitors will surely enjoy surfing through your site!
Full Screen Vertical Scroll Snap
Author: Adam Argyle
This is a basic animation that speeds up movement whenever a visitor scrolls.
Scrolling Gradient
Author: Mike
An animation that adapts a background gradient depending on the scroll position.
Ghibli Slider
Author: Adam Kuhn
A visually appealing slideshow animation that was built through a collaboration with Studio Ghibli, the popular animation company.
Return to the Scroll Effects of the Future!
Author: Tim Pietrusky
This group of scroll animations includes a list of nine different animations split into different categories. Each of these effects is premade, so you can apply them at your leisure.
Agency website POC
Author: Jamie Coulter
Another great tool for businesses looking to spruce up their website, this animation includes many eye-catching features.
Scrolling Story Cards
Author: Mike England
An animation that works great as a timeline for your website.
Parallax Scrolling animations
Author: Sonia Grant
This tool includes multiple animations that create a full-size website with many elements. If you’re looking for an all-in-one tool, this is for you.
[Pure CSS] – One page scroll
Author: Quentin Veron
A very simple one-page scroll. It doesn’t even have one line of JavaScript!
High Performance Parallax
Author: nK
This animation smoothly displays images for your visitors by slowly revealing them, or by hiding the picture as you scroll. This encourages visitors to stay for longer and maintains interest.
Scroll-Triggered Animations (jQuery)
Author: Bramus
A group of eight interesting intro animations that can be easily implemented into any website.
Stacking Cards, Final Version
Author: Bramus
An animation that displays falling info cards that stack onto each other, building a pile of information by the end of the page.
Trigger a CSS animation on scroll
Author: bellachen
Another simple animation with flying text and wobbling images that will catch the eyes of your website visitors.
Overlapping sections only CSS
Author: Henry Zarza
An animation that uses overlapping text to build a falling line of text using position: sticky.
smoove.js css3 scroll effects
Author: Yifang Di
This animation is showcased through four groups of three images each. Each of these groups is demonstrated differently, but each in its own impressive way. They are bound to have a strong impression on your visitors.
CSS-Only Horizontal Parallax Gallery
Author: Paulina Hetman
This program showcases Paris photos in an experimental gallery. It uses perspective and color to draw visitors in while letting visitors have a part in building those elements.
CSS Animations on Scroll – Fade From Bottom up
Author: Rxn
A simple CSS animation that fades blocks in and out of view when scrolling up and down.
IntersectionObserver demo/test
Author: David Aerne
A simple CSS Animation with very little source code that creates a gradient background as you scroll. Although the background will stay a single solid color at first, as you scroll throughout the page a different color will take its place temporarily.
CSS Fixed Conic Fill
Author: Adam Argyl
Another gradient-based animation, but this one changes the text color by revealing a “fixed to viewport” background gradient.
CSS Animations on Scroll – Multi Step Move v2
Author: mmanindarkumar
A simple animation that displays elements moving within multiple steps.
CSS background change on scroll
Author: Giana
This CSS background features a fixed element that changes color depending on which page section it enters. This gives each image its own extra flair while leaving its original splendor intact.
Untitled
Author: Felipe Teixeira
Another multifaceted group of animations that would work well anywhere on your website.
Scrolling half by half pure #CSS by @Kseso
Author: Kseso
A fun demo using pure CSS animation. While scrolling through, each side will leave one half for a new image, and soon afterward switch. It’s a very useful tool that easily catches the eye.
FAQ on CSS Animations on Scroll
What is a CSS animation on scroll?
CSS animation on scroll combines standard CSS animations with scroll detection techniques. Unlike traditional animations that play automatically, these effects trigger when specific elements enter the viewport. They use JavaScript event listeners or newer APIs like Intersection Observer to determine when elements become visible.
The browser continuously checks element positions during scrolling. When an element reaches the viewport, a class gets added that activates pre-defined keyframe animations. This creates the illusion that scrolling itself causes the animation.
The technical implementation typically involves:
// Modern approach using Intersection Observer
const observer = new IntersectionObserver(entries => {
entries.forEach(entry => {
if (entry.isIntersecting) {
entry.target.classList.add('animate');
}
});
});
document.querySelectorAll('.animate-on-scroll').forEach(element => {
observer.observe(element);
});
This approach significantly improves performance compared to older scroll event methods.
How do I create scroll-triggered animations in CSS?
Creating effective scroll-based animations requires understanding several technologies:
- CSS animations for defining the visual effects
- Scroll event handling for detecting position
- DOM manipulation for applying animation classes
Start with basic keyframe animations in your CSS:
@keyframes fadeInUp {
from {
opacity: 0;
transform: translateY(30px);
}
to {
opacity: 1;
transform: translateY(0);
}
}
.fade-in-up {
animation: fadeInUp 0.6s ease forwards;
opacity: 0; /* Start hidden */
}
Then use Intersection Observer API (or libraries like AOS or GSAP ScrollTrigger) to detect when elements enter the viewport:
// Using a library like AOS makes implementation simpler
document.addEventListener('DOMContentLoaded', function() {
AOS.init({
offset: 120,
delay: 0,
duration: 400,
easing: 'ease',
once: false,
mirror: false
});
});
For production sites, consider these implementation details:
- Add proper animation timing functions for natural movement
- Include fallbacks for browsers with limited support
- Test performance on lower-end mobile devices
Why use CSS animations on scroll?
CSS animations tied to scrolling directly improve key Core Web Vitals metrics when implemented correctly. Here’s why they matter:
Improved engagement metrics:
- Average session duration increases by 15-40% with interactive content
- Bounce rates typically decrease 10-30% with proper visual feedback
- Conversion rates improve through guided visual attention
Enhanced visual storytelling:
- Creates natural information hierarchy through sequential reveals
- Guides users through complex concepts step-by-step
- Connects information points through visual relationships
Accessibility and technical benefits (when properly implemented):
- Respects user preferences via
prefers-reduced-motionmedia queries - Improves perceived performance through progressive content loading
- Highlights important content changes for screen reader users when properly marked
Real-world data from e-commerce sites shows properly implemented scroll effects can increase product page conversion by 6-8% compared to static presentations.
Can CSS animations affect performance?
Yes. Poor animation implementation directly harms Core Web Vitals, especially Cumulative Layout Shift (CLS) and First Input Delay (FID). Common performance issues include:
- Layout thrashing – forcing browser to recalculate positions repeatedly
- Paint storms – triggering excessive repaints across large screen areas
- Main thread blocking – running complex calculations during scrolling
To maintain 60fps smooth animations:
/* Properties that trigger cheap GPU compositing */
.performant-animation {
transform: translateY(20px); /* Good: uses GPU */
opacity: 0.8; /* Good: uses GPU */
}
/* Properties that cause expensive repaints */
.problematic-animation {
left: 20px; /* Avoid: triggers layout */
margin-top: 10px; /* Avoid: triggers layout */
box-shadow: 0 0 10px rgba(0,0,0,0.5); /* Expensive paint */
}
Tools to measure animation performance:
- Chrome DevTools Performance panel
- Layout shift regions in Chrome DevTools
- requestAnimationFrame timing analysis
When optimized correctly, scroll animations can actually improve perceived performance by directing attention during content loading processes.
What are some popular CSS animation libraries?
Several animation libraries have emerged to simplify scroll-triggered animations implementation:
GSAP (GreenSock Animation Platform):
- Exceptional performance with 60fps animations
- Powerful ScrollTrigger plugin specifically for scroll animations
- Advanced timeline control for complex sequences
// GSAP ScrollTrigger example
gsap.to(".element", {
scrollTrigger: {
trigger: ".element",
start: "top 80%",
end: "bottom 20%",
scrub: true,
markers: true
},
x: 300,
rotation: 360,
duration: 3
});
AOS (Animate On Scroll):
- Lightweight with simple implementation
- Good browser compatibility
- HTML-attribute based configuration
Intersection Observer Utilities:
- Native browser API with growing support
- Minimal performance impact
- Foundation for custom animation systems
Each library offers different tradeoffs between ease of use, performance, and control. For critical applications, GSAP typically provides the best performance metrics despite its larger file size.
How do I implement CSS scroll animations without JavaScript?
Pure CSS scroll animations without JavaScript have limited functionality but work for specific use cases:
/* Using scroll-behavior for smooth page navigation */
html {
scroll-behavior: smooth;
}
/* Using scroll-snap for controlled scrolling positions */
.container {
scroll-snap-type: y mandatory;
overflow-y: scroll;
height: 100vh;
}
.section {
scroll-snap-align: start;
height: 100vh;
}
/* Sticky positioning for parallax-like effects */
.parallax-bg {
position: sticky;
top: 0;
z-index: -1;
height: 100vh;
}
CSS-only techniques include:
- Scroll-snap properties for controlled paging effects
- Position: sticky for simple parallax behavior
- CSS scroll-timeline (experimental) for scroll-linked animations
While these methods have excellent performance, they lack the flexibility and browser support of JavaScript-enhanced approaches. They work well for simple effects but struggle with complex multi-element sequences.
Are scroll animations responsive?
Responsive scroll animations require additional consideration beyond typical responsive design:
- Viewport-relative sizing – use vh/vw units or CSS variables adjusted via media queries
- Threshold adjustments – modify when animations trigger based on screen size
- Duration scaling – adjust animation timing for different devices
/* Base animation properties */
.animate-element {
--animation-distance: 50px;
--animation-duration: 0.8s;
}
/* Adjust for smaller screens */
@media (max-width: 768px) {
.animate-element {
--animation-distance: 30px;
--animation-duration: 0.5s;
}
}
.animate-element.in-view {
animation: slideIn var(--animation-duration) forwards;
}
@keyframes slideIn {
from {
transform: translateY(var(--animation-distance));
opacity: 0;
}
to {
transform: translateY(0);
opacity: 1;
}
}
Testing across devices is critical – animations that look subtle on desktop may feel jarring on mobile where content occupies more relative screen space. User testing shows preferred animation intensity typically decreases as screen size decreases.
Can animations be combined with parallax effects?
Parallax scrolling combined with scroll-based animations creates depth through multi-speed movement. This combination enhances spatial understanding and creates immersive experiences.
Effective implementation uses transform properties to avoid performance issues:
.parallax-container {
perspective: 1px;
height: 100vh;
overflow-x: hidden;
overflow-y: scroll;
}
.parallax-back {
transform: translateZ(-1px) scale(2);
}
.parallax-base {
transform: translateZ(0);
}
.parallax-front {
transform: translateZ(0.5px) scale(0.5);
}
When animations are added to parallax elements, timing becomes critical:
// Adding animations to parallax layers
ScrollTrigger.create({
trigger: ".section-1",
start: "top bottom",
end: "bottom top",
scrub: true,
animation: gsap.timeline()
.to(".parallax-front .element", {
x: 100,
opacity: 1,
duration: 1
})
});
For best results, use animation speeds that complement the parallax movement rate – faster parallax typically pairs well with slower animations to prevent visual confusion.
How do I troubleshoot issues with scroll animations?
When scroll effect CSS isn’t working properly, follow this debugging process:
Step 1: Verify scroll detection Add visual indicators to confirm scroll events are firing:
// Debug logging for scroll detection
document.addEventListener('scroll', () => {
console.log(`Scroll position: ${window.scrollY}`);
});
// For Intersection Observer
const debugObserver = new IntersectionObserver(entries => {
entries.forEach(entry => {
console.log(`Element visibility: ${entry.isIntersecting}`);
console.log(`Intersection ratio: ${entry.intersectionRatio}`);
});
}, {threshold: [0, 0.1, 0.5, 1]});
Step 2: Check animation definitions Isolate animations from scroll triggers to verify they work independently:
/* Test animation directly */
.test-animation {
animation: fadeIn 1s forwards !important; /* Override any conditions */
}
Step 3: Inspect browser compatibility Use feature detection rather than browser detection:
// Check for Intersection Observer support
if ('IntersectionObserver' in window) {
// Use modern approach
} else {
// Use fallback
}
Common pitfalls:
- Animation elements have
display: none(can’t be measured) - Z-index issues causing elements to animate behind others
- CSS specificity problems overriding animation classes
- Performance throttling on mobile devices
Browser developer tools’ Animation Inspector and Performance panels provide insights for complex animation debugging.
What are examples of scroll animations in use?
Real-world implementations of CSS animation on scroll solve specific business and communication challenges:
Apple product pages use subtle scroll animations to:
- Reveal product features progressively
- Create 3D space through parallax movement
- Guide attention to technical specifications
News sites like The New York Times use scroll animations for:
- Data visualization sequencing
- Long-form article engagement
- Visual storytelling in journalistic content
E-commerce platforms implement scroll effects to:
- Highlight product features through timed reveals
- Create more engaging category browsing
- Improve product comparison interactions
The key difference between successful and distracting implementations is purpose – effective animations serve specific communication goals rather than merely decorating the page.
Conclusion
CSS animations on scroll transform static websites into dynamic experiences when implemented correctly. They create natural visual hierarchy, guide user attention, and improve engagement metrics – all contributing to better conversion rates.
Key implementation takeaways:
- Accessibility first: Always respect user preferences through
prefers-reduced-motionand ensure animations don’t create barriers - Performance focus: Use transform and opacity for smooth animations, avoid layout-triggering properties
- Purpose-driven design: Each animation should serve a specific user experience goal, not just decorate
Technical best practices:
- Use Intersection Observer API instead of scroll events when possible
- Test animations across devices with various processing capabilities
- Implement progressive enhancement so content remains accessible when animations fail
The future of scroll-based transitions will continue evolving with upcoming APIs like CSS Scroll-Linked Animations (currently in development), which will allow even more performant native implementations without JavaScript.
For developers starting with scroll animations, focus first on subtle effects that guide users naturally without calling attention to the animation itself. As your skills advance, more complex sequences can create truly memorable experiences that differentiate your site and effectively communicate your brand’s message.
If you liked this article about CSS animations on scroll, you should check out this article about CSS animation libraries.
There are also similar articles discussing cool CSS buttons, CSS shadow effects, CSS blockquotes, and CSS blur effects.
And let’s not forget about articles on CSS charts, CSS headers, CSS parallax effects, and CSS page transitions.
