The AbortSignal.timeout() static method returns an abort signal that automatically aborts after a specified duration.

The align-content property vertically aligns content in block layouts, like it does in flex or grid layouts.

The transform-box CSS property sets the position and dimensions of the reference box relative to which an element's transformations are calculated.

The Intl.Segmenter API creates a locale-aware text splitter that can separate a string into meaningful graphemes, words, or sentences.

The paint-order CSS property sets the z-order of strokes, fills, and (in SVG content) markers. For example, paint-order: markers stroke fill; draws the markers, then stroke on top of markers, then fill on top of both markers and stroke.

The white-space-collapse CSS property sets whether new line characters are shown as line breaks, and whether multiple consecutive spaces are all displayed or combined.

The AbortSignal.any() static method combines an iterable of abort signals into a single signal, with the abort reason taken from the first signal to abort.

The i32.add, i32.sub, i32.mul, i64.add, i64.sub, and i64.mul operations extend constant expressions to include arithmetic.

The Promise.withResolvers() static method is an alternative to the Promise() constructor that returns both the promise and resolution functions. You can use this to access resolve and reject outside the scope of the executor function.

The checkVisibility() method checks if an element is potentially visible, with optional parameters for the kinds of visibility to check. For example, it checks whether the element has the style display: none, but can also check for visibility: hidden.

The transfer() and transferToFixedLength() methods of ArrayBuffer move a buffer from one context to another (for example, to a worker).

The Object.groupBy() and Map.groupBy() static methods group values of arrays and iterables based on a function that returns a key for each value.

The shadowrootmode attribute on <template> creates a shadow root without the use of JavaScript. It is a declarative alternative to the attachShadow() method.

AVIF (AV1 Image File Format) is an image format based on the AV1 video format.

The Array.fromAsync() static method copies items from an async iterable object to make a new array.

The rect() CSS function creates a rectangle shape with insets from the edges of an element. The xywh() CSS function creates a rectangle shifted by an x and y distance. They can be used with clip-path and shape-outside.

The loading="lazy" attribute for <img> and <iframe> elements blocks loading the external resource until the user scrolls to that element's part of the page.

The :has() CSS functional pseudo-class matches an element if any of the selectors passed as parameters would match at least one element.

The createImageBitmap() global method creates an ImageBitmap object from a source such as an image, SVG, blob, or canvas. An ImageBitmap object represents pixel data that can be drawn to a canvas with lower latency than other types, such as ImageData.

The imagesrcset and imagesizes attributes with the rel="preload" attribute for the <link> HTML element starts fetching responsive images before they're found in the body of the document.

The counter-set CSS property creates (and optionally sets a value for) a counter, the numbers for a series of headings or ordered list items.

The preservesPitch property for <audio> or <video> adjusts the pitch of audio to sound more natural when the playback rate is faster or slower than the default.

The reset() method clears a canvas to its initial state.

The cap CSS length unit corresponds to the height of Latin capital letters.

The linear() easing function for animations and transitions interpolates linearly between the control points, and can be used to approximate complex easing functions, such as a bounce effect.

CSS nesting allows for shorter selectors, easier reading, and more modularity by nesting rules inside others.

The scripting CSS media query sets styles based on whether scripting such as JavaScript is available. Values are enabled if scripting is available, initial-only if scripting is only available on page load (for example, printed content), or none.

The mask CSS property (and several longhand properties) partially or completely hides an element according to the shape and depth of an image.

The :dir() CSS functional pseudo-class matches elements by text direction, either right to left (rtl) or left to right (ltr).

The pow(), sqrt(), hypot(), log(), and exp() CSS functions compute various exponential functions.