The Temporal API allows you to work with dates, times, time zones, and durations. It is more powerful than the Date API.
Web platform features
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 corner-shape CSS property sets the shape of an element's corners when using border-radius, allowing for shapes other than rounded corners. For example, corner-shape: squircle is a shape in between a square and rounded corner.
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 cancel() method of a TransformStream transformer cleans up resources when the readable side cancels or the writable side aborts.
The <select> element's appearance, including the button, selected option, picker dropdown, and options, can be customized using CSS.
Anchor positioning places an element based on the position of another element. For example, you can place a tooltip next to the content it references.
The line-clamp CSS property limits the text in a block container to a certain number of lines. The prefixed -webkit-line-clamp is widely supported but only works with -webkit-box-orient: vertical in combination with display: -webkit-box or display: -webkit-inline-box.
The interpolate-size CSS property sets whether animations and transitions interpolate between a numeric value and a keyword value, such as from a fixed length to auto or fit-content.
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 @function CSS at-rule defines a custom function that takes CSS values or custom properties as arguments, and returns a CSS value. It can be based on conditional logic such as by using the @media at-rule.
The if() CSS function is an inline conditional value that returns a value based on a set of conditions.
The calc-size() CSS function computes mathematical expressions that include height and width keyword values, for example calc-size(fit-content, size / 2). Not to be confused with the calc() CSS function, which cannot use keyword values.
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The JPEG XL image format is a raster graphics file format that supports animation, alpha transparency, and lossy as well as lossless compression.
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The when() method on a event target returns an Observable object, which provides a declarative API for subscribing to and operating on events. It's an alternative to addEventListener() callbacks.
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The attr() CSS function, in the context of any property, returns the value of an attribute of an HTML element, with the option to return it as a specific type or unit. You can set a default value for missing or invalid attributes.
The loading="lazy" attribute for <video> and <audio> elements defers loading the media resource until the element is near the viewport. This matches the lazy-loading behavior for <img> and <iframe> elements.
The navigator.gpu API performs operations such as rendering and computation on dedicated graphics hardware (also known as a Graphics Processing Unit).
The requestIdleCallback() API queues a function that runs in idle browser time, either at the end of a frame or when the user is inactive. Also known as the background tasks API.
The navigator.share() method invokes the device's native sharing mechanism and passes text, links, files, and other content to share targets. Also known as the Web Share API.
The switch attribute, when present on an <input type="checkbox"> HTML element, renders a switch control with an on and off state instead of a checkbox control.
Module import … with { type: "css" } statements load CSS modules as constructable stylesheets. Also known as CSS module scripts.
The flex-wrap: balance CSS declaration distributes items in a multi-line flex container such that each line has about the same number of items.
The overlay CSS property, used as an allow-discrete CSS transition, prevents a top layer element, such as a popover or a <dialog>, from being removed from the top layer before it has finished animating. You can't set the value of the overlay property; only use it as transition property.