📃 December 2018 release notes

Newly available

The following features are newly available:

Constraint validation API: Methods that validate form controls before submission, such as checkValidity(), reportValidity() and setCustomValidity().
Interaction media queries: The pointer, any-pointer, hover, and any-hover CSS media queries set styles based on the presence of pointing devices and their ability to hover over elements. For example, most smartphones match the (hover: none) and (pointer: coarse) media query.

The following features are now widely available:

ANGLE_instanced_arrays WebGL extension: The ANGLE_instanced_arrays extension for WebGL 1.0 contexts draws the same object multiple times or groups of similar objects multiple times, if the group shares the same vertex data, primitive count and type.
EXT_texture_filter_anisotropic WebGL extension: The EXT_texture_filter_anisotropic extension for WebGL 1.0 and 2.0 contexts adds anisotropic filtering (AF). AF improves the quality of mipmapped texture access when viewing a textured primitive at an oblique angle.

The following features are now available in Chrome:

Fullscreen API: The fullscreen API makes a specific element fill the whole screen and hides most browser UI.
globalThis: The globalThis property accesses the global this value (and hence the global object itself) across environments.
Intl.RelativeTimeFormat: The Intl.RelativeTimeFormat API creates a locale-aware formatter that turns an object representing a relative time (such as '1 day ago') into a localized string.

The following features are now available in Chrome Android:

Fullscreen API: The fullscreen API makes a specific element fill the whole screen and hides most browser UI.
globalThis: The globalThis property accesses the global this value (and hence the global object itself) across environments.
Intl.RelativeTimeFormat: The Intl.RelativeTimeFormat API creates a locale-aware formatter that turns an object representing a relative time (such as '1 day ago') into a localized string.

The following features are now available in Firefox:

Fullscreen API: The fullscreen API makes a specific element fill the whole screen and hides most browser UI.
scrollbar-color: The scrollbar-color CSS property sets the color of the scrollbar track and thumb.
scrollbar-width: The scrollbar-width CSS property sets the width of the scrollbar.
Non-trapping float-to-int conversion (WebAssembly): Saturating floating-point to integer conversion operators return the maximum or minimum integer value on overflow instead of trapping.

The following features are now available in Firefox for Android:

Fullscreen API: The fullscreen API makes a specific element fill the whole screen and hides most browser UI.
prefers-reduced-motion media query: The prefers-reduced-motion CSS media query sets styles based on whether the user prefers to minimize the amount of non-essential animations on the device, such as scrolling, panning, zooming, and strobing.
scrollbar-color: The scrollbar-color CSS property sets the color of the scrollbar track and thumb.
scrollbar-width: The scrollbar-width CSS property sets the width of the scrollbar.
Non-trapping float-to-int conversion (WebAssembly): Saturating floating-point to integer conversion operators return the maximum or minimum integer value on overflow instead of trapping.