Navigation Timing API Viewer - Online Page Load Breakdown
See your current page load broken down into DNS, TLS, request, and DOM phases. Understand where time is spent.
UD5 Toolkit
Experience smooth, native page-state transitions — no heavy libraries required.
Checking support...Click the purple circle or any dashed zone to morph the shape across the stage. Each move uses view-transition-name for seamless element-level animation.
Each card has a unique view-transition-name. Click any card — it smoothly morphs to fill the row while siblings reflow around it.
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Select a thumbnail to smoothly transition the preview. Each thumbnail maps to an element with its own view-transition-name.
Toggle between grid and list layouts. Items reflow smoothly — the entire layout transition is captured by the API.
The JavaScript behind these transitions is surprisingly simple:
| Browser | Version | Support | Notes |
|---|---|---|---|
| Chrome | 111+ | Full | Full support for multi-page & SPA transitions |
| Edge | 111+ | Full | Same engine as Chrome; full feature parity |
| Opera | 97+ | Full | Chromium-based, supports all features |
| Safari | 18+ | Partial | SPA transitions supported; multi-page in development |
| Firefox | — | Not yet | Under active development; expected in future release |
| Chrome Android | 111+ | Full | Mobile-optimized transitions work smoothly |
| Safari iOS | 18+ | Partial | SPA mode supported; improving rapidly |
document.startViewTransition() and can customize it via CSS pseudo-elements like ::view-transition-old and ::view-transition-new.view-transition-name work? view-transition-name CSS property tags an element so the browser can track it across states. When two elements (old and new) share the same name, the browser morphs between them — animating position, size, and shape changes seamlessly. Each name must be unique on the page at any given moment. This enables impressive effects like cards expanding, images moving between galleries, or buttons transforming into modals.::view-transition-old(root) and ::view-transition-new(root) for the page-level cross-fade, or use the element's view-transition-name like ::view-transition-old(my-element). Set animation-duration, animation-timing-function, and even animation-delay. You can also use CSS custom properties to dynamically control these values from JavaScript, as demonstrated in this tool's controls above.if (document.startViewTransition) before using.document.startViewTransition(). Unlike CSS transitions which require predefined start/end states, the View Transitions API automatically handles the animation between any two states. This dramatically simplifies transition logic in frameworks — no more complex animation libraries for basic page transitions.<meta name="view-transition" content="same-origin"> tag to both pages. The browser will then automatically cross-fade between them. For more control, you can use CSS to customize the transition or add view-transition-name to elements on both pages for element-level morphing. This works without any JavaScript.view-transition-name, there can be a slight memory overhead. Best practice: only assign view-transition-name to elements that actually need to morph (typically 1-10 elements per transition), and keep transitions under 500ms for the best user experience.if (typeof document.startViewTransition === 'function') { /* supported */ }. This returns true for browsers with SPA transition support. For multi-page support detection, check if the @view-transition CSS at-rule is recognized. Always wrap your transition code with this check and provide a direct DOM update as fallback for unsupported browsers.document.startViewTransition() method returns a ViewTransition object with a skipTransition() method. Call transition.skipTransition() to immediately finish the transition without animation. The object also has ready, finished, and updateCallbackDone promises for fine-grained control over the transition lifecycle. This is useful for handling rapid successive transitions or user interruptions.See your current page load broken down into DNS, TLS, request, and DOM phases. Understand where time is spent.
See your current page load broken down into DNS, TLS, request, and DOM phases. Understand where time is spent.
Write JavaScript using element.animate() and see the result in a live preview. Compare with CSS keyframes. Debugger included.
Create an animation that advances with scroll using animation‑timeline: scroll(). See the visual timeline editor. Modern CSS.
Customize falling snow particles with pure CSS or canvas. Adjust speed, size, and wind. Copy the code for your website.
Limit browser gestures on an element: pan‑x, pinch‑zoom, manipulation. Draw on a canvas to test. Mobile dev helper.
Define the initial scroll position for a scroll container with scroll‑start. Test with and without snapping. New feature.
Draw shapes and experiment with globalCompositeOperation. See Porter‑Duff operators in action. Great for game devs.
Use CSS masks and fixed backgrounds to create a unique parallax reveal effect. Copy the code. No JavaScript.
Create a pure CSS scroll progress indicator using animation‑timeline: scroll(). No JavaScript. Copy the complete code.
Render the classic Stanford Bunny with a basic WebGPU pipeline. Rotate and zoom. Check if your browser supports WebGPU.
Configure how your PWA launches: focus existing or create new. Test with the launch_handler manifest field.
Paste GeoJSON and instantly see it drawn on a draggable map. Supports points, lines, and polygons. Local fetch of tiles.
Create CSS mask‑image effects with custom shapes, gradients, and SVGs. Visually see the mask applied to an image. Copy the CSS.
Toggle content‑visibility: auto on long blocks and see the rendering time difference. Understand this powerful property.
Apply content‑visibility: auto to off‑screen sections and see the rendering cost drop. Demos for infinite scroll optimization.
Adjust root, margin, and threshold. See a live log of intersection events as you scroll. Debug lazy loading.
Create a custom element with named slots and see content projection in action. Learn Web Components basics.
A customisable Matrix‑style digital rain animation. Adjust speed, characters, and colors. Fullscreen mode for ambiance.
Write or paste HTML, CSS, and JavaScript and instantly see the rendered output in a sandboxed iframe. A handy frontend prototyping tool.
Create promises that resolve or reject after a delay. See state changes and chain .then/.catch. Debug async code.
See exact dimensions of your current browser inner/outer window, screen resolution, and pixel ratio. Developer debug.
Create a properly styled 'Skip to Content' link. Customize target and appearance. Essential for keyboard users. Copy the HTML/CSS.
Check if your site has a visible and functional skip navigation link. Key for keyboard‑only users.
See how overflow: visible, hidden, scroll, and auto behave with real content. Clone to test with your text.
Take a screenshot of the current browser tab using Screen Capture API. Crop, annotate with text and arrows, and download as PNG. Local only.
Pixelate selected areas of an image to hide faces or sensitive data. Adjust block size. Download the censored result.
Write a generator function and step through it with next(). See values and done state. Understand iterators.
Visually create the glassmorphism effect: background blur, transparency, and border. Copy the complete CSS. Modern UI design.
Pixelate or censor parts of an image by dragging. Adjust block size for mosaic effect. Useful for hiding faces or sensitive data. Client-side processing.