Audio Tracks

Method of specifying and selecting between multiple audio tracks. Useful for providing audio descriptions, director's commentary, additional languages, alternative takes, etc.

CSS font-stretch

If a font has multiple types of variations based on the width of characters, the `font-stretch` property allows the appropriate one to be selected. The property in itself does not cause the browser to stretch to a font.

selector list argument of :not()

Selectors Level 3 only allowed `:not()` pseudo-class to accept a single simple selector, which the element must not match any of. Thus, `:not(a, .b, [c])` or `:not(a.b[c])` did not work. Selectors Level 4 allows `:not()` to accept a list of selectors. Thus, `:not(a):not(.b):not([c])` can instead be written as `:not(a, .b, [c])` and `:not(a.b[c])` works as intended.

Multiple file selection

Allows users to select multiple files in the file picker.

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.

htmlselectelement api: multiple

html element: select: multiple