294559 2025-06-16 08:22:24 -0700 CSS.supports('break-after', 'avoid') returns true despite no support 2025-06-23 08:23:12 -0700 1 1 1 Unclassified WebKit New Bugs Safari 18 Unspecified Unspecified NEW InRadar P2 Normal --- 1 caugner webkit-unassigned webkit-bug-importer oldest_to_newest 2123961 0 caugner 2025-06-16 08:22:24 -0700 **Background**: Safari doesn't support `[page-]break-before/after: avoid`. **Expected**: `CSS.supports('break-after', 'avoid')` should return `false`. **Actual**: `CSS.supports('break-after', 'avoid')` returns `true`. --- The following all return `true`, although the features aren't implemented : ```js CSS.supports('break-before', 'avoid'); CSS.supports('break-after', 'avoid'); CSS.supports('page-break-before', 'avoid'); // legacy CSS.supports('page-break-after', 'avoid'); // legacy ``` (`page-break-inside: avoid` and `break-inside: avoid` are omitted here, as these _are_ implemented, see bug 34080.) --- To check, you can also run the MDN BCD Collector tests (which use `CSS.supports()` to determine support): - break-before: https://mdn-bcd-collector.gooborg.com/tests/css/properties/break-before - break-after: https://mdn-bcd-collector.gooborg.com/tests/css/properties/break-after - page-break-before: https://mdn-bcd-collector.gooborg.com/tests/css/properties/page-break-before - page-break-after: https://mdn-bcd-collector.gooborg.com/tests/css/properties/page-break-after 2125229 1 webkit-bug-importer 2025-06-23 08:23:12 -0700 <rdar://problem/154095900>