154669 2016-02-24 23:39:28 -0800 CSS.supports returns false for custom properties 2022-08-01 09:10:28 -0700 1 1 1 Unclassified WebKit CSS WebKit Nightly Build All OS X 10.11 RESOLVED FIXED https://drafts.csswg.org/css-conditional-3/#the-css-interface InRadar P2 Normal --- 1 50167214 rniwa 50167214 abecsi ahmad.saleem792 ap betravis bfulgham cdumez claude.pache cmarcelo davidbarr ddkilzer dino hyatt jonlee kling pf rniwa sgospodarets webkit-bug-importer zalan oldest_to_newest 1168042 0 50167214 2016-02-24 23:39:28 -0800 1. Run CSS.supports('--foo', 'red') on the JavaScript console What is the expected result? true getting logged in the console What happens instead? false getting logged in the console As custom properties (aka CSS variables) are now supported in Chromium, CSS.supports('--foo', 'red') should return true. The alternative method signature using a conditionText works already correct and returns true for CSS.supports('(--foo: red)') The related specification can be found here: https://drafts.csswg.org/css-conditional-3/#the-css-interface See also: https://crbug.com/584683(Blink fixed) 1221423 1 ddkilzer 2016-08-19 12:15:05 -0700 https://twitter.com/traviskaufman/status/766672149566423040 1299936 2 sgospodarets 2017-04-21 15:21:16 -0700 Visual Demo- https://codepen.io/malyw/pen/OmXMYb 1299952 3 sgospodarets 2017-04-21 15:47:00 -0700 The problem is, that this bug breaks most of the CSS Custom Properties detection examples across the Web. And introduces inconsistencies and confusion as it works in CSS, but not in JS. 1300035 4 webkit-bug-importer 2017-04-21 17:54:26 -0700 <rdar://problem/31770186> 1887846 5 ahmad.saleem792 2022-07-30 06:39:24 -0700 I am able to reproduce this bug using test case from Comment 02 and Safari 15.6 on macOS 12.5 shows "FALSE" for "window.CSS.supports('--a', 0);" while all other browsers (Chrome Canary 106 and Firefox Nightly 105) show "TRUE". Just wanted to share updated test results. Thanks! 1887925 6 rniwa 2022-07-30 23:01:12 -0700 Pull request: https://github.com/WebKit/WebKit/pull/2881 1887992 7 ews-feeder 2022-07-31 15:53:13 -0700 Committed 252987@main (69362356a5ab): <https://commits.webkit.org/252987@main> Reviewed commits have been landed. Closing PR #2881 and removing active labels.