September 2024 web platform update

Now widely available on the web platform

Widely available

• appearance: The appearance CSS property controls the appearance of form controls. Using appearance: none disables any default native appearance and allows the elements to be styled with CSS. Learn more.

• Array at(): The at() method of arrays and typed arrays returns the item at an index, including negative indices for getting items relative to the end of an array. Also known as the relative indexing method. Learn more.

• ::backdrop: The ::backdrop CSS pseudo-element is a box underneath an element in the top layer, such as a <dialog>. It can be used to create obscuring effects distinguishing a modal element from the elements underneath. Learn more.

• background-attachment: The background-attachment CSS property sets whether an element's background image or gradient moves as the element scrolls. Learn more.

• BroadcastChannel: The BroadcastChannel API allows you to send messages between same-origin browsing contexts, such as between the same page loaded in multiple tabs. Learn more.

• Cascade layers: The @layer CSS at-rule avoids specificity conflicts by providing priority levels for different groups of CSS rules, such as low-priority styles like resets, and high-priority styles like UI components. Learn more.

• Layout containment: The contain: layout CSS declaration isolates the inside of an element such that it cannot affect the layout of the rest of the page or be affected by the rest of the page. This permits the browser to avoid slower layout calculations. Learn more.

• Paint containment: The contain: paint CSS declaration prevents an element's descendants from being drawn outside the boundaries of the containing element, with any overflow clipped. This permits the browser to avoid slower painting calculations. Learn more.

• Size containment: The contain: size CSS declaration sets an element's dimensions exclusively by its height and width properties, ignoring its contents and descendants. This permits the browser to avoid slower layout calculations. Learn more.

• <dialog>: The <dialog> HTML element represents a modal or non-modal dialog box, such as a confirmation prompt or a subwindow used to enter data. Learn more.

• :focus-visible: The :focus-visible CSS pseudo-class selects elements that match the :focus pseudo-class and meets the browser's criteria for visually emphasizing focused elements. Learn more.

• hardwareConcurrency: The navigator.hardwareConcurrency read-only property returns the number of logical processors available to run threads on the user's computer. Learn more.

• scroll-behavior: The scroll-behavior CSS property controls whether scrolling is smooth or snaps, for scroll actions not performed by the user such as those triggered by navigation. Learn more.

• String at(): The at() method of strings returns the character (one UTF-16 code unit) at an index, including negative indices for getting the character relative to the end of the string. Also known as the relative indexing method. Learn more.

• structuredClone(): The structuredClone() global method creates a deep copy of an object. Values that cannot be cloned can instead be transferred, making the original value no longer usable. Learn more.

• text-combine-upright: The text-combine-upright CSS property displays multiple characters in the space of a single character in vertical text. This is used in East Asian documents to display Latin-based strings such as components of a date or letters of an initialism. Learn more.

• text-emphasis: The text-emphasis CSS property sets position and style for text emphasis marks, especially for East Asian languages. Learn more.

• 3D transforms: The transform CSS property and its 3D transform functions allow rotations and other transforms in three dimensions, including perspective transforms. Learn more.

• Locks: The navigator.locks API coordinates work with shared resources through mutually exclusive ownership of a resource's name. Also known as web locks. Learn more.

Newly available on the web platform

Newly available

• backdrop-filter: The backdrop-filter CSS property applies graphical effects such as blurring or color shifting to the area behind an element. Learn more.

• willReadFrequently: The optional willReadFrequently parameter of a canvas's getContext() method permits the browser to optimize for frequent getImageData() calls by avoiding hardware acceleration. Also known as multiple readback. Learn more.

• content-visibility: The content-visibility CSS property delays rendering an element, including layout and painting, until it is needed. Learn more.

• cookieEnabled: The navigator.cookieEnabled property returns a Boolean value for whether the browser accepts or ignores attempts to write cookie data. Learn more.

• Mutually exclusive <details> elements: Multiple <details> elements which use the same name attribute are mutually exclusive. When one member of the group is opened, all other members are closed. Learn more.