CSS Scroll-Driven Animation Generator
Animate elements natively as they enter the viewport. Utilize the modern animation-timeline specification to generate pure CSS scroll magic without relying on heavy JavaScript libraries like GSAP or ScrollMagic.
What is a CSS Scroll-Driven Animation?
For over a decade, developers had to rely on the browser’s main JavaScript thread to detect scroll events. We would write event listeners that fired hundreds of times per second, checking if an element had crossed the threshold of the viewport, and then manually toggling CSS classes to trigger an animation.
The modern CSS Scroll-Driven Animation specification changes everything. By introducing properties like animation-timeline, the browser can natively tie the progress of a CSS @keyframes animation directly to the scroll position of the user’s screen. No event listeners, no JavaScript, just pure, native layout rendering.
The End of ScrollMagic and GSAP?
If you have ever built a heavily animated marketing page, you are likely familiar with libraries like GSAP (GreenSock), ScrollMagic, or Framer Motion. While these tools remain incredibly powerful for complex, timeline-sequenced SVG manipulations, they are entirely overkill for simple “reveal on scroll” effects.
Loading a 50kb JavaScript library just to make a card slide up when a user scrolls down is terrible for your Core Web Vitals. This pure css scroll animation tool outputs native code that replaces 90% of the use cases for these heavy libraries, dramatically improving your site’s load speed and Total Blocking Time (TBT).
Understanding animation-timeline: view()
The magic behind this generator is the view() function. When you apply animation-timeline: view(); to an element, you are telling the browser: “Link this animation to the element’s intersection with the screen.”
animation-range. Setting it to entry 0% cover 30% tells the browser to start the animation exactly when the element touches the bottom of the screen, and finish the animation when 30% of the element is visible. This prevents animations from triggering too early or too late!Performance Benefits: Off the Main Thread
Why are native CSS scroll animations so important? It comes down to the Main Thread.
When a user scrolls on a mobile device, the phone’s CPU is working hard to paint new pixels. If you use JavaScript to calculate scroll bounds simultaneously, you block the CPU, causing severe stuttering and “jank”. Native CSS animation-timeline runs entirely on the browser’s Compositor Thread (via hardware GPU acceleration). This guarantees flawlessly smooth 60fps animations, even on low-tier, older mobile devices.
Browser Support & Polyfill Fallbacks
Because animation-timeline is a relatively modern specification (introduced around Chrome 115), you must handle fallbacks gracefully. Currently, Chromium browsers (Chrome, Edge, Brave) support it natively, while Safari and older Firefox versions may ignore it.
Our code is completely safe to use in production today. We utilize the @supports rule in the generated CSS. If a user is on an unsupported browser (like an old iPhone), the animation is simply bypassed, and the element displays normally. This Progressive Enhancement approach ensures your site remains fully functional for everyone.
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Frequently Asked Questions
Does this scroll animation require JavaScript?
No. This generator utilizes the native CSS animation-timeline specification. It requires zero JavaScript, zero event listeners, and completely replaces heavy libraries like GSAP or ScrollMagic for basic intersection animations.
What browsers support animation-timeline?
As of late 2023, the specification is fully supported in all Chromium-based browsers (Google Chrome, Microsoft Edge, Opera, Brave). Support for Safari and Firefox is actively in development and expected shortly.
How do I handle older browsers that don’t support this?
The code output by this tool is wrapped in an @supports (animation-timeline: view()) feature query. If a user is on Safari or an older browser, the browser simply ignores the animation rules and renders the element fully visible immediately. This guarantees your site never breaks.