10+ Resize Observer API Examples

This is a Container-Aware Plotly Chart. It forces a data visualization component to respond strictly to its parent element’s dimensions rather than the global window size. Its function is to prevent layout breakages in complex dashboards where sidebars toggle or CSS Grid tracks resize dynamically without triggering a global window resize event. (Requires: plotly-js)

This is a Staggered Text Scroll Reveal. It parses structural typography into independent animated lines. Its function is to pace the reader’s attention, transforming static paragraphs into dynamic narrative elements triggered by viewport intersection. (Requires: gsap-js, scroll-trigger-js, lenis-js, split-type)

This is a Matcap Instanced Disco Geometry demo. It renders multiple unique 3D geometries (Torus Knot, Icosahedron, Torus) using the WebGL Instanced Mesh technique. Instead of drawing individual planes for every mirror on the surface of the shape, it creates one InstancedMesh per object, mathematically orienting thousands of tiny reflective mirrors to mimic a faceted, crystal-like disco surface. (Requires: Three.js)

This Interactive Neon Grid Trail creates a sleek, cybernetic atmosphere ideal for tech portfolios or futuristic landing pages. It utilizes the HTML5 Canvas API to render a grid of invisible squares that light up in neon teal upon interaction. The effect features a “memory” mechanic where the illuminated cells hold their charge for a moment before gracefully fading back into the darkness, creating a satisfying trail behind the user’s cursor.

This Smart CSS Anchored Selection Pills component demonstrates the bleeding edge of CSS layout capabilities. It uses the new CSS Anchor Positioning API to tether a visual “pill” indicator to the currently selected radio button without JavaScript calculations for position. The demo includes a robust fallback system that calculates positions via ResizeObserver for browsers that don’t yet support anchors, ensuring a consistent experience across the board. It also features advanced masking techniques (SVG and CSS Filters) to create “knockout” text effects where the selected text changes color inversely to the pill background. (Requires: GSAP, Tweakpane)

This WebGL Fluid Smoke Button elevates standard UI interactions by embedding a real-time generative shader directly into the interface. Instead of using a heavy video file, it calculates complex fluid dynamics on the fly using Fractional Brownian Motion (fBM). The result is a mesmerizing, never-repeating smoky background that reacts to hover states with a smooth scale and rotation effect, styled effortlessly via Tailwind CSS. (Requires: fragment-canvas, Tailwind CSS)

Features a smooth article reading progress indicator built with React Hooks and ResizeObserver, with scroll handling optimized using passive event listeners for superior performance.

A demonstration of high-performance font size auto-fitting to container width using ResizeObserver and CSS variables, ensuring smooth scaling of h1 headings while preventing layout thrashing via requestAnimationFrame.

Efficient Container-Aware image loading with ResizeObserver and optimized candidate selection (DPI awareness, size tolerance, aspect ratio matching), actively preventing the download of unnecessarily large image files.