The :playing, :paused, :seeking, :buffering, :stalled, :muted, and :volume-locked CSS pseudo-classes match <audio> and <video> elements based on their state.

The border-shape CSS property sets the geometry of the border box, changing the shape of any applicable border, border image, focus outline, or shadow.

The startViewTransition() method of an Element object starts a view transition that affects only that element's DOM tree. You can use this to run separate elements' transitions concurrently.

WebXR layer types, such as XRCylinderLayer, XRCylinderLayer, XREquirectLayer, XRProjectionLayer or XRQuadLayer, are managed by the system compositor, to reduce latency or resampling.

Crash reporting sends a report to a URL nominated by the Reporting-Endpoints header when a user is unable to continue using the page because the browser or tab crashed.

The CloseWatcher API listens and responds to close requests on in-page components, such as modals, popovers, and sidebars.

The captureStream() method for <audio> and <video> elements returns a MediaStream for the media element's content. You can use this to record media or send it elsewhere, such as a canvas or WebRTC connection.

Scroll-triggered animations start and stop CSS animations when an element is within or outside a scrolling range. It's an alternative to applying styles with the IntersectionObserver API. Not to be confused with scroll-driven animations.

The precommitHandler callback option to NavigateEvent's intercept() method returns a promise that defers navigation until the promise resolves. You can use this to change the navigation's URL, state, and history before navigation occurs.

The <meta name="text-scale" content="scale" /> HTML element allows the browser's initial font size to be affected by the operating system text scale settings. The <meta name="text-scale" content="legacy" /> element is the default behavior that respects only browser font-size settings.

The Sanitizer API customizes the sanitization of HTML parsed and inserted into the DOM in a way that can prevent cross-site scripting attacks. You can use it with DOM APIs that accept a sanitizer option, such as parseHTML() or setHTML().

The CustomElementRegistry() constructor creates a new custom element registry that's separate from the global window.customElements registry. Creating more than one registry is useful for multiple custom elements that have the same tag name to coexist.

The overflow-clip-margin CSS property sets how far overflow content may appear outside the bounds of an element before it's clipped by effects such as overflow: clip.

The hidden="until-found" attribute hides an element until it is found using the browser's find-in-page search or it is directly navigated to by following a URL fragment.

The column-wrap and column-height CSS properties control when columns in a multicolumn layout wrap or overflow. You can use this to constrain the height of columns within a taller box or to create two-dimensional column layouts.

The window.crashReport object is a key-value store to record information about your application's state. If there's a crash, then the data in the key-value store is sent to your crash reporting endpoint, to help you pinpoint the cause of the crash.

The confidence property of a navigation performance entry describes whether the navigation metric is likely to be representative the page's performance (high confidence) or affected by transient conditions, such as browser startup (low confidence).

The "local-network-access" user permission (and certain actions that imply this permission, such as a fetch() request with { targetAddressSpace: "local" }) allows a site to send requests to servers on a user's local network.

The text-justify CSS property sets the justification method of text when text-align: justify is set.

The initialPermissionStatus property of the HTMLGeolocationElement API represents whether geolocation was previously granted, denied, or neither, when the page first loads.

The <geolocation> HTML element represents a button that, upon activation, prompts the user to choose whether to grant the page access to geolocation data.

The subgroups extension for the WebGPU Shading Language (WGSL) enables SIMD parallelism. Using subgroups, threads in a workgroup can efficiently communicate and perform collective operations.

The caret-shape CSS property sets the shape of the insertion caret, the symbol that shows where the next character is to be inserted or deleted.

The clipboardchange event for navigator.clipboard fires when the user modifies the clipboard's contents.

The Temporal API allows you to work with dates, times, time zones, and durations. It is more powerful than the Date API.

The navigator.gpu API performs operations such as rendering and computation on dedicated graphics hardware (also known as a Graphics Processing Unit).

The position-visibility: anchors-valid and position-visibility: anchors-visible CSS declarations are aliases for anchor-valid and anchor-visible.

Module import … with { type: "css" } statements load CSS modules as constructable stylesheets. Also known as CSS module scripts.

Provides access to raw mouse movement by locking the target of mouse events to a single element and hiding the mouse cursor.

The accent-color CSS property sets a color for checkboxes, radio buttons, and other form controls.