145874 2015-06-10 22:54:58 -0700 @supports parse error with the filter property when no parameter is specified 2021-09-11 00:42:12 -0700 1 1 1 Unclassified WebKit CSS 528+ (Nightly build) Unspecified Unspecified RESOLVED INVALID P2 Normal --- 1 phiw2 webkit-unassigned benjamin chrisjshull jh718.park simon.fraser oldest_to_newest 1101232 0 254708 phiw2 2015-06-10 22:54:58 -0700 Created attachment 254708 test case @supports (filter:blur()) or (-webkit-filter: blur()) { /* do something */ } is parsed as valid by Webkit but not by Firefox (the rules inside the `@supports` block are applied by Webkit nightly builds). Note the missing parameter for the blur value. Chromium based browsers appear to suffer from the same issue (tested with Opera 30). Note: 1. Webkit handles this correctly for `@supports (transform:scale()) {}` and ignores everything inside the @supports block. 2. -webkit-backdrop-filter: blur() is also affected 1103676 1 phiw2 2015-06-20 18:25:36 -0700 Well, after multiple readings of the relevant spec [1], I think I’m wrong – and Webkit (+ Blink) is correct. filter: blur() or filter: grayscale(), etc without a parameter is actually valid per the mentioned spec. The spec mentions - quote (for blur()): “The lacuna value for interpolation is…”. The word ‘lacuna’ apparently refers to ‘missing parameter’. I had to ask two native English speakers for this; the relevant MDN article [2] confirms this reading (“If no parameter is provided, then a value 0 is used”). By extension @supports (filter: blur()) [or other filters] should parse as valid (prefixed atm of course). [1] http://www.w3.org/TR/filter-effects/#FilterProperty [2] https://developer.mozilla.org/en-US/docs/Web/CSS/filter 1792663 2 jh718.park 2021-09-11 00:42:12 -0700 Per the bug reporter's comment, close this bug as non-issue. 254708 2015-06-10 22:54:58 -0700 2015-06-10 22:54:58 -0700 test case webkit-at-support-error.html text/html 449 phiw2 PCFET0NUWVBFIGh0bWw+CjxodG1sIGxhbmc9ImVuIiBkaXI9Imx0ciI+CjxoZWFkPgo8bWV0YSBj aGFyc2V0PSJ1dGYtOCI+Cjx0aXRsZT50ZXN0PC90aXRsZT4KPG1ldGEgbmFtZT0idmlld3BvcnQi IGNvbnRlbnQ9IndpZHRoPWRldmljZS13aWR0aCwgaW5pdGlhbC1zY2FsZT0xIj4KPHN0eWxlIHR5 cGU9InRleHQvY3NzIj4KZGl2IHsKCXdpZHRoOiAxMDBweDsKCWhlaWdodDogMTAwcHg7CgliYWNr Z3JvdW5kOiBncmVlbjsKfQpAc3VwcG9ydHMgKGZpbHRlcjpibHVyKCkpIG9yICgtd2Via2l0LWZp bHRlcjogYmx1cigpKSB7CglkaXYgeyBiYWNrZ3JvdW5kOiByZWQ7IH0KfQo8L3N0eWxlPgoKPC9o ZWFkPgo8Ym9keT4KCTxwPiBUaGVyZSBzaG91bGQgYmUgYSBncmVlbiBzcXVhcmUgYmVsb3cgKGFu ZCBub3QgYSByZWQgb25lKSA8cD4KCjxkaXY+PC9kaXY+Cgo8L2JvZHk+CjwvaHRtbD4=