Meta tracking bug for all issues here: 1170774

Non-standard APIs and Properties required for Web Compatibility

This page contains a list of CSS and DOM properties & APIs required for compatibility with the de-facto (mobile) web.

Each is grouped into a group of relative priority, as perceived by the Web Compat team (based on known issues in Bugzilla and webcompat.com and other investigations).

Parts of this list will eventually make its way into the Compatibility Standard.

This document of WebKit stuff implemented in Microsoft Edge also serves as a guide, though not everything will be as important for Gecko.

CSS Features

Tracker bug for CSS changes: 1170789

High Priority

• Enable layout.css.prefixes.webkit by default 1213126 (Turn on in 46, for non-RELEASE builds)
• -webkit-flexbox 12083441208635 (Landed in 45 & 46 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit- prefixed gradients 1210575 (Landed in 44 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-transforms 1179444 (Landed in 44 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-transitions 1179437 (Landed in 44 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-background-clip: text 759568 (Landed in 48 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-text-stroke 1248708 (Landed in 48 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-text-fill-color 1247777 (Landed in 48 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)

Medium Priority

• -webkit-appearance (or at least -moz-appearance to behave in the same way 605985) (Fixed)
• -background-position-x/y 550426 (Landed in 49 Nightly)
• @media (-webkit-transform-3d) 1239799 (Landed in 46 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)

Lower Priority

• -webkit-device-pixel-ratio 1176968 (Landed in 45 Aurora/Nightly, but disabled behind layout.css.prefixes.device-pixel-ratio-webkit until Google Docs is fixed)
• -webkit-animation 1179408 (Landed in 44 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-border* 1179393 (Landed in 44 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-filter 1236506 (Landed in 46 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-mask-* 1242617 (Landed in 47 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• -webkit-mask-border-* 1244492

Needs investigation to understand potential compat impact

• -webkit-column* 1179406

Super Hard but would fix many cosmetic issues (maybe create more?)

• max-width 100% inside of table (975632 + blockers/dependencies, related, etc). In the process of trying to understand this bug, I went on a journey to graph the dependencies.

DOM APIs

Tracker bug for DOM changes: 1170774

High Priority

• window.orientation/orientationchange event 920734 (shipping in 44)
• WebKitCSSMatrix 717722 (Landed in 46 Aurora/Nightly. Ships when layout.css.prefixes.webkit=true rides the trains - 1213126)
• window.event 218415 (fixed)

Medium Priority

• innerText 264412 (shipping in 45)
• webkitMatchesSelector 1216193 (shipping in 44)
• file.webkitrelativepath 1258490 (shipping in 49)
• input.webkitdirectory 1258489 (fixed)

Needs investigation to understand potential compat impact

• webkitFullscreen 1179457

Video

Highest priority omg so many friggin sites don't work

• HLS video (.m3u8). 577084 (Legal bug: 1016449)