The EXT_disjoint_timer_query extension for WebGL 1.0 contexts measures the duration of a set of GL commands, without stalling the rendering pipeline.

The toolname, tooldescription, and toolautosubmit HTML form element attributes register actions that can be called by in-browser AI agents or browser extensions. Also known as declarative WebMCP.

A <canvas> HTML element with the layoutsubtree attribute can draw descendant elements in its rendering context. You can use it to style and layout text in a canvas, expose canvas content to browser features (like accessibility, translate, or find-in-page), and apply 2D and 3D effects to HTML.

The setHTML(), replaceWithHTML(), beforeHTML(), prependHTML(), appendHTML() and afterHTML() DOM methods, and unsafe equivalents, insert HTML into an existing tree.

The streamHTML(), streamReplaceWithHTML(), streamBeforeHTML(), streamPrependHTML(), streamAppendHTML() and streamAfterHTML() DOM methods, and unsafe equivalents, return writeable streams that incrementally insert HTML into an existing tree.

The headingoffset HTML attribute offsets the heading level of descendant <h1>–<h6> elements. The headingreset HTML attribute prevents heading offset computation from traversing beyond the element.

The :heading and :heading() CSS pseudo-classes match headings of varying levels. The :heading pseudo-class matches any heading (<h1> through <h6>). The :heading() selector matches any of the given levels. For example, :heading(1, 2) matches headings level 1 and 2.

Module import … assert { type: "json" } and import … assert { type: "css" } JavaScript statements load JSON and CSS data.

Subresource integrity violation reporting sends a report to a URL nominated by the Reporting-Endpoints header or the ReportingObserver API when a resource request violates an integrity check.

The link-parameters CSS property, param() modifier for the url() CSS function, and the #:~:param(…) URL fragment set custom CSS environment variables on an external resource, such as an SVG image, allowing the external resource to adapt its presentation based on the variables.

The Magnetometer API reads magnetic field sensor data from the device's magnetometer.

MathML specifies several elements and attributes that are not included in MathML Core. Math applications outside of browsers may implement these features, but they are discouraged for web use.

Mutation events like DOMSubtreeModified, DOMNodeInserted, or DOMNodeRemoved fire when DOM changes occur.

The createValueRange() for form elements, such as <textarea> or <input type="text">, gets an OpaqueRange object that represents a live span of text. You can use this for range-based operations on the input text, such as setting custom highlights or placing autocomplete popovers.

The <portal> HTML element embeds another page into the current page as a non-interactive preview.

The Access-Control-Request-Private-Network: true and Access-Control-Allow-Private-Network: true HTTP request and response headers establish permission for websites to make requests to internal networks, such as to routers.

The frame-sizing CSS property sets the size of an <iframe> element to that of it contents, to avoid scrolling in the iframe. Embedded documents allow this with the <meta name="responsive-embedded-sizing"> element and request resizing in the embedding page by calling window.requestResize().

The line-height-step CSS property creates consistent vertical rhythm by setting the spacing between body text baselines. It rounds taller lines like headings up to the next multiple of the body text spacing.

The sharedStorage API stores data to a shared space where the data can then be processed without the ability to track users across the different sites they visit. A common use case is measuring the reach of third-party ads without using user-tracking cookies.

The SpeechRecognition.grammars property of the Web Speech API represents a set of words or patterns of words that the recognition service should recognize, used for when the recognition service's accuracy is low.

Attributes and properties of table elements, such as align, vAlign, noWrap, bgcolor, or char set various visual presentation properties of the table and its sections and cells.

The topics API reports a user's likely subject-matter interests (as determined by the browser, known as topics) to iframes. This allows for interest-based advertising that does not rely on user's exact browsing history, third-party cookies, or fingerprinting.

The cancel() method of a TransformStream transformer cleans up resources when the readable side cancels or the writable side aborts.

The _localized suffixed members of the web app manifest set translated names, descriptions, icons, and shortcuts. The browser automatically selects resources based on the user's language and region settings.

The WebNN API constructs and executes computational graphs of neural networks by making use of the various machine learning capabilities and hardware accelerators available on the device. Also known as Web Neural Network API.

The navigator.getVRDisplays() API represents virtual reality (VR) devices, including sensors and head-mounted displays.

The color-contrast() CSS function picks a color from a list that has the most contrast with another color.

The display: contents CSS declaration sets an element to display only its contents, not itself.

The document.modelContext API registers page actions that can be called by in-browser AI agents or browser extensions. Also known as WebMCP.

The element() CSS function creates a live-updating image from an HTML element that can be used as an image or background image.