Free Browser Compatibility Testing on Mozilla Firefox 57

ELEMENTS NOT SUPPORTED IN FIREFOX 57 BROWSER

CSS line-clamp

Proprietary and undocumented CSS property that will contain text to a given amount of lines when used in combination with display: -webkit-box. It will end with ellipsis when text-overflow: ellipsis is included.

Explicit descendant combinator >>

An explicit, non-whitespace spelling of the descendant combinator. A >> B is equivalent to A B.

Media Queries: interaction media features

Allows a media query to be set based on the presence and accuracy of the user's pointing device, and whether they have the ability to hover over elements on the page. This includes the pointer, any-pointer, hover, and any-hover media features.

selector list argument of :nth-child and :nth-last-child CSS pseudo-classes

The newest versions of :nth-child() and :nth-last-child() accept an optional of S clause which filters the children to only those which match the selector list S. For example, :nth-child(1 of .foo) selects the first child among the children that have the foo class (ignoring any non-foo children which precede that child). Similar to :nth-of-type, but for arbitrary selectors instead of only type selectors.

CSS Reflections

Method of displaying a reflection of an element

prefers-reduced-motion media query

CSS media query based on a user preference for preferring reduced motion (animation, etc).

inputmode attribute

The inputmode attribute specifies what kind of input mechanism would be most helpful for users entering content into the form control.

HTML Media Capture

Facilitates user access to a device's media capture mechanism, such as a camera, or microphone, from within a file upload control.

seamless attribute for iframes

The seamless attribute makes an iframe's contents actually part of a page, and adopts the styles from its hosting page. The attribute has been removed from both the WHATWG and the W3C HTML5 specifications.

Video Tracks

Method of specifying and selecting between multiple video tracks. Useful for providing sign language tracks, burnt-in captions or subtitles, alternative camera angles, etc.