Status

This page documents the implementation status of various HTML and CSS features in Blitz.

CSS Properties HTML Elements Events WPT Tests

This page documents Blitz's scores on the "css" subsuite of the Web Platform Tests.

Note: As it does not have a JavaScript engine, Blitz can only run about 20% of the total subtests. In the numbers below, tests that Blitz can't run are ignored and percentages are relative to the number of tests run.

Data from commit:
1093b86 wpt: skip non-UTF-8 test files instead of crashing (#659) (2026-08-09)

wpt / css / css-view-transitions

Area	Interop Score	Tests	Test %	Subtests	Subtest %
Total	29.50%	(91/308)	29.55%	(91/308)	29.55%
navigation	40.00%	(2/5)	40.00%	(2/5)	40.00%
nested	66.60%	(20/30)	66.67%	(20/30)	66.67%
scoped	32.20%	(10/31)	32.26%	(10/31)	32.26%

Test	Subtests	Subtest %	Status
3d-transform-incoming.html	(0/1)	0.00%	FAIL
3d-transform-outgoing.html	(0/1)	0.00%	FAIL
active-view-transition-on-non-root.html	(1/1)	100.00%	PASS
active-view-transition-pseudo-class-match.html	(0/1)	0.00%	FAIL
active-view-transition-type-on-non-root.html	(1/1)	100.00%	PASS
animating-new-content-subset.html	(0/1)	0.00%	FAIL
animating-new-content.html	(0/1)	0.00%	FAIL
animation-name-ua-prefix.html	(0/1)	0.00%	FAIL
auto-name-from-id-shadow.html	(0/1)	0.00%	FAIL
auto-name-from-id.html	(0/1)	0.00%	FAIL
auto-name.html	(0/1)	0.00%	FAIL
backdrop-filter-animated.html	(1/1)	100.00%	PASS
backdrop-filter-captured.html	(1/1)	100.00%	PASS
backdrop-filter-while-promise-pending.html	(1/1)	100.00%	PASS
block-with-overflowing-text.html	(0/1)	0.00%	FAIL
break-inside-avoid-child.html	(1/1)	100.00%	PASS
capture-old-state-error-flag-cleanup.html	(1/1)	100.00%	PASS
capture-with-offscreen-child-translated.html	(0/1)	0.00%	FAIL
capture-with-offscreen-child.html	(0/1)	0.00%	FAIL
capture-with-opacity-zero-child.html	(0/1)	0.00%	FAIL
capture-with-visibility-hidden-child.html	(0/1)	0.00%	FAIL
capture-with-visibility-mixed-descendants.html	(0/1)	0.00%	FAIL
class-specificity.html	(0/1)	0.00%	FAIL
clip-path-larger-than-border-box-on-child-of-named-element.html	(0/1)	0.00%	FAIL
column-span-during-transition-doesnt-skip.html	(0/1)	0.00%	FAIL
content-smaller-than-box-size.html	(0/1)	0.00%	FAIL
content-visibility-auto-shared-element.html	(0/1)	0.00%	FAIL
content-with-child-with-transparent-background.html	(0/1)	0.00%	FAIL
content-with-clip-root.html	(0/1)	0.00%	FAIL
content-with-clip.html	(0/1)	0.00%	FAIL
content-with-inline-child.html	(1/1)	100.00%	PASS
content-with-transform-new-image.html	(0/1)	0.00%	FAIL
content-with-transform-old-image.html	(0/1)	0.00%	FAIL
content-with-transparent-background.html	(0/1)	0.00%	FAIL
css-tags-paint-order-with-entry.html	(0/1)	0.00%	FAIL
css-tags-paint-order.html	(0/1)	0.00%	FAIL
css-tags-shared-element.html	(0/1)	0.00%	FAIL
dialog-in-rtl-iframe.html	(1/1)	100.00%	PASS
dialog-in-top-layer-during-transition-new.html	(0/1)	0.00%	FAIL
dialog-in-top-layer-during-transition-old.html	(0/1)	0.00%	FAIL
element-is-grouping-during-animation.html	(0/1)	0.00%	FAIL
element-stops-grouping-after-animation.html	(1/1)	100.00%	PASS
element-with-overflow.html	(0/1)	0.00%	FAIL
empty-render-target-capture.html	(1/1)	100.00%	PASS
escaped-name.html	(1/1)	100.00%	PASS
exit-transition-with-anonymous-layout-object.html	(0/1)	0.00%	FAIL
far-away-capture.html	(0/1)	0.00%	FAIL
fractional-box-new.html	(0/1)	0.00%	FAIL
fractional-box-old.html	(0/1)	0.00%	FAIL
fractional-box-with-overflow-children-new.html	(0/1)	0.00%	FAIL
fractional-box-with-overflow-children-old.html	(0/1)	0.00%	FAIL
fractional-box-with-shadow-new.html	(0/1)	0.00%	FAIL
fractional-box-with-shadow-old.html	(0/1)	0.00%	FAIL
fractional-translation-from-position.html	(1/1)	100.00%	PASS
fractional-translation-from-transform.html	(1/1)	100.00%	PASS
fragmented-at-start-ignored.html	(0/1)	0.00%	FAIL
fragmented-during-transition-skips.html	(1/1)	100.00%	PASS
hit-test-unpainted-element.html	(0/1)	0.00%	FAIL
hit-test-unrelated-element.html	(0/1)	0.00%	FAIL
html-becomes-fixed.html	(0/1)	0.00%	FAIL
iframe-and-main-frame-transition-new-main-new-iframe.html	(0/1)	0.00%	FAIL
iframe-and-main-frame-transition-new-main-old-iframe.html	(0/1)	0.00%	FAIL
iframe-and-main-frame-transition-old-main-new-iframe.html	(0/1)	0.00%	FAIL
iframe-and-main-frame-transition-old-main-old-iframe.html	(0/1)	0.00%	FAIL
iframe-and-main-frame-transition-old-main.html	(0/1)	0.00%	FAIL
iframe-and-main-frame-transition-with-name-on-iframe.html	(0/1)	0.00%	FAIL
iframe-new-has-scrollbar.html	(1/1)	100.00%	PASS
iframe-old-has-scrollbar.html	(1/1)	100.00%	PASS
iframe-transition.sub.html	(1/1)	100.00%	PASS
inline-child-with-composited-filter.html	(1/1)	100.00%	PASS
inline-child-with-filter.html	(1/1)	100.00%	PASS
inline-child-with-overflow-shadow.html	(0/1)	0.00%	FAIL
inline-element-size.html	(0/1)	0.00%	FAIL
inline-with-offset-from-containing-block.html	(0/1)	0.00%	FAIL
japanese-tag.html	(0/1)	0.00%	FAIL
massive-element-below-and-on-top-of-viewport-partially-onscreen-new.html	(1/1)	100.00%	PASS
massive-element-below-and-on-top-of-viewport-partially-onscreen-old.html	(1/1)	100.00%	PASS
massive-element-below-viewport-offscreen-new.html	(0/1)	0.00%	FAIL
massive-element-below-viewport-offscreen-old.html	(0/1)	0.00%	FAIL
massive-element-below-viewport-partially-onscreen-new.html	(1/1)	100.00%	PASS
massive-element-below-viewport-partially-onscreen-old.html	(1/1)	100.00%	PASS
massive-element-left-of-viewport-offscreen-new.html	(0/1)	0.00%	FAIL
massive-element-left-of-viewport-offscreen-old.html	(0/1)	0.00%	FAIL
massive-element-left-of-viewport-partially-onscreen-new.html	(1/1)	100.00%	PASS
massive-element-left-of-viewport-partially-onscreen-old.html	(1/1)	100.00%	PASS
massive-element-on-top-of-viewport-offscreen-new.html	(0/1)	0.00%	FAIL
massive-element-on-top-of-viewport-offscreen-old.html	(0/1)	0.00%	FAIL
massive-element-on-top-of-viewport-partially-onscreen-new.html	(1/1)	100.00%	PASS
massive-element-on-top-of-viewport-partially-onscreen-old.html	(1/1)	100.00%	PASS
massive-element-right-and-left-of-viewport-partially-onscreen-new.html	(1/1)	100.00%	PASS
massive-element-right-and-left-of-viewport-partially-onscreen-old.html	(1/1)	100.00%	PASS
massive-element-right-of-viewport-offscreen-new.html	(0/1)	0.00%	FAIL
massive-element-right-of-viewport-offscreen-old.html	(0/1)	0.00%	FAIL
massive-element-right-of-viewport-partially-onscreen-new.html	(1/1)	100.00%	PASS
massive-element-right-of-viewport-partially-onscreen-old.html	(1/1)	100.00%	PASS
match-element-name.html	(0/1)	0.00%	FAIL
modify-style-via-cssom.html	(0/1)	0.00%	FAIL
multiline-span-with-overflowing-text-and-box-decorations.html	(0/1)	0.00%	FAIL
named-element-with-fix-pos-child-new.html	(1/1)	100.00%	PASS
named-element-with-fix-pos-child-old.html	(1/1)	100.00%	PASS
names-are-tree-scoped.html	(0/1)	0.00%	FAIL
nested-elements-in-overflow.html	(0/1)	0.00%	FAIL
new-and-old-sizes-match.html	(1/1)	100.00%	PASS
new-content-ancestor-clipped-2.html	(0/1)	0.00%	FAIL
new-content-ancestor-clipped.html	(0/1)	0.00%	FAIL
new-content-captures-clip-path.html	(0/1)	0.00%	FAIL
new-content-captures-different-size.html	(0/1)	0.00%	FAIL
new-content-captures-opacity.html	(0/1)	0.00%	FAIL
new-content-captures-positioned-spans.html	(0/1)	0.00%	FAIL
new-content-captures-root.html	(0/1)	0.00%	FAIL
new-content-captures-spans.html	(0/1)	0.00%	FAIL
new-content-changes-overflow-left.html	(0/1)	0.00%	FAIL
new-content-changes-overflow.html	(0/1)	0.00%	FAIL
new-content-container-writing-modes.html	(0/1)	0.00%	FAIL
new-content-element-writing-modes.html	(0/1)	0.00%	FAIL
new-content-escapes-clip-with-abspos-child.html	(0/1)	0.00%	FAIL
new-content-flat-transform-ancestor.html	(0/1)	0.00%	FAIL
new-content-from-root-display-none.html	(0/1)	0.00%	FAIL
new-content-has-scrollbars.html	(1/1)	100.00%	PASS
new-content-inline-with-offset-from-containing-block-clipped.html	(0/1)	0.00%	FAIL
new-content-intrinsic-aspect-ratio.html	(0/1)	0.00%	FAIL
new-content-is-empty-div.html	(0/1)	0.00%	FAIL
new-content-is-inline.html	(0/1)	0.00%	FAIL
new-content-object-fit-fill.html	(0/1)	0.00%	FAIL
new-content-object-fit-none.html	(0/1)	0.00%	FAIL
new-content-object-view-box-clip-path-reference.html	(0/1)	0.00%	FAIL
new-content-object-view-box-clip-path.html	(0/1)	0.00%	FAIL
new-content-object-view-box-overflow-clipped.html	(0/1)	0.00%	FAIL
new-content-object-view-box-overflow.html	(0/1)	0.00%	FAIL
new-content-preserve-3d-ancestor.html	(0/1)	0.00%	FAIL
new-content-root-scrollbar-with-fixed-background.html	(0/1)	0.00%	FAIL
new-content-scaling.html	(0/1)	0.00%	FAIL
new-content-transform-change-001.html	(0/1)	0.00%	FAIL
new-content-transform-position-fixed.html	(0/1)	0.00%	FAIL
new-content-with-object-view-box.html	(0/1)	0.00%	FAIL
new-content-with-overflow-zoomed.html	(0/1)	0.00%	FAIL
new-content-with-overflow.html	(0/1)	0.00%	FAIL
new-element-on-start.html	(0/1)	0.00%	FAIL
new-root-vertical-writing-mode.html	(0/1)	0.00%	FAIL
no-named-elements.html	(0/1)	0.00%	FAIL
no-painting-while-render-blocked.html	(1/1)	100.00%	PASS
no-root-capture.html	(1/1)	100.00%	PASS
no-white-flash-before-activation.html	(1/1)	100.00%	PASS
nothing-captured.html	(1/1)	100.00%	PASS
object-view-box-new-image.html	(0/1)	0.00%	FAIL
object-view-box-old-image.html	(0/1)	0.00%	FAIL
offscreen-element-modified-before-coming-onscreen.html	(0/1)	0.00%	FAIL
old-content-captures-clip-path.html	(0/1)	0.00%	FAIL
old-content-captures-different-size.html	(0/1)	0.00%	FAIL
old-content-captures-opacity.html	(0/1)	0.00%	FAIL
old-content-captures-root.html	(0/1)	0.00%	FAIL
old-content-container-writing-modes.html	(0/1)	0.00%	FAIL
old-content-element-writing-modes.html	(0/1)	0.00%	FAIL
old-content-escapes-clip-with-abspos-child.html	(0/1)	0.00%	FAIL
old-content-has-scrollbars.html	(1/1)	100.00%	PASS
old-content-inline-with-offset-from-containing-block-clipped.html	(0/1)	0.00%	FAIL
old-content-intrinsic-aspect-ratio.html	(0/1)	0.00%	FAIL
old-content-is-empty-div.html	(0/1)	0.00%	FAIL
old-content-is-inline.html	(0/1)	0.00%	FAIL
old-content-object-fit-fill.html	(0/1)	0.00%	FAIL
old-content-object-fit-none.html	(0/1)	0.00%	FAIL
old-content-object-view-box-clip-path-reference.html	(0/1)	0.00%	FAIL
old-content-object-view-box-clip-path.html	(0/1)	0.00%	FAIL
old-content-object-view-box-overflow.html	(0/1)	0.00%	FAIL
old-content-root-scrollbar-with-fixed-background.html	(0/1)	0.00%	FAIL
old-content-with-object-view-box.html	(0/1)	0.00%	FAIL
old-content-with-overflow-zoomed.html	(0/1)	0.00%	FAIL
old-content-with-overflow.html	(0/1)	0.00%	FAIL
old-root-vertical-writing-mode.html	(0/1)	0.00%	FAIL
outer-padding-inner-background.html	(0/1)	0.00%	FAIL
paint-holding-in-iframe.html	(0/1)	0.00%	FAIL
pseudo-element-overflow-clip-with-border-radius.html	(0/1)	0.00%	FAIL
pseudo-element-overflow-hidden.html	(0/1)	0.00%	FAIL
pseudo-element-preserve-3d.html	(0/1)	0.00%	FAIL
pseudo-rendering-invalidation.html	(0/1)	0.00%	FAIL
pseudo-with-classes-entry.html	(0/1)	0.00%	FAIL
pseudo-with-classes-exit.html	(0/1)	0.00%	FAIL
pseudo-with-classes-match-ident.html	(0/1)	0.00%	FAIL
pseudo-with-classes-match-multiple-wildcard.html	(0/1)	0.00%	FAIL
pseudo-with-classes-match-multiple.html	(0/1)	0.00%	FAIL
pseudo-with-classes-match-wildcard-no-star.html	(0/1)	0.00%	FAIL
pseudo-with-classes-match-wildcard.html	(0/1)	0.00%	FAIL
pseudo-with-classes-mismatch-ident.html	(0/1)	0.00%	FAIL
pseudo-with-classes-mismatch-partial.html	(0/1)	0.00%	FAIL
pseudo-with-classes-mismatch-wildcard.html	(0/1)	0.00%	FAIL
pseudo-with-classes-multiple-vt-classes.html	(0/1)	0.00%	FAIL
pseudo-with-classes-new-with-class-old-without.html	(0/1)	0.00%	FAIL
pseudo-with-classes-old-with-class-new-without.html	(0/1)	0.00%	FAIL
pseudo-with-classes-view-transition-group.html	(0/1)	0.00%	FAIL
pseudo-with-classes-view-transition-image-pair.html	(0/1)	0.00%	FAIL
reset-state-after-scrolled-view-transition.html	(1/1)	100.00%	PASS
root-captured-as-different-tag.html	(0/1)	0.00%	FAIL
root-style-change-during-animation.html	(0/1)	0.00%	FAIL
root-to-shared-animation-end.html	(0/1)	0.00%	FAIL
root-to-shared-animation-incoming.html	(0/1)	0.00%	FAIL
root-to-shared-animation-start.html	(1/1)	100.00%	PASS
rotated-cat-off-top-edge.html	(1/1)	100.00%	PASS
rtl-with-scrollbar.html	(1/1)	100.00%	PASS
scroller-child-abspos.html	(1/1)	100.00%	PASS
scroller-child.html	(1/1)	100.00%	PASS
scroller.html	(1/1)	100.00%	PASS
set-current-time-transform.html	(0/1)	0.00%	FAIL
set-current-time.html	(0/1)	0.00%	FAIL
set-universal-specificity.html	(0/1)	0.00%	FAIL
shadow-part-with-class-inside-shadow-important.html	(0/1)	0.00%	FAIL
shadow-part-with-class-inside-shadow.html	(0/1)	0.00%	FAIL
shadow-part-with-class.html	(0/1)	0.00%	FAIL
shadow-part-with-name-nested.html	(0/1)	0.00%	FAIL
shadow-part-with-name-overridden-by-important.html	(1/1)	100.00%	PASS
shadow-part-with-name.html	(0/1)	0.00%	FAIL
sibling-frames-transition.html	(0/1)	0.00%	FAIL
small-scale.html	(0/1)	0.00%	FAIL
snapshot-containing-block-absolute.html	(1/1)	100.00%	PASS
snapshot-containing-block-includes-scrollbar-gutter.html	(1/1)	100.00%	PASS
snapshot-containing-block-static-iframe.html	(1/1)	100.00%	PASS
snapshot-containing-block-static.html	(0/1)	0.00%	FAIL
span-with-overflowing-text-and-box-decorations.html	(0/1)	0.00%	FAIL
span-with-overflowing-text-hidden.html	(0/1)	0.00%	FAIL
span-with-overflowing-text.html	(0/1)	0.00%	FAIL
table-caption.html	(0/1)	0.00%	FAIL
transform-origin-view-transition-group.html	(0/1)	0.00%	FAIL
transformed-element-scroll-transform.html	(1/1)	100.00%	PASS
transition-in-empty-iframe.html	(1/1)	100.00%	PASS
update-callback-called-once.html	(0/1)	0.00%	FAIL
view-transition-name-is-backdrop-filter-root.html	(1/1)	100.00%	PASS
view-transition-name-is-grouping.html	(1/1)	100.00%	PASS
view-transition-name-on-document-root.html	(1/1)	100.00%	PASS
view-transition-name-removed-mid-transition.html	(1/1)	100.00%	PASS
view-transition-name-stacking-context-dynamic.html	(0/1)	0.00%	FAIL
view-transition-types-match-early-mutation.html	(0/1)	0.00%	FAIL
view-transition-types-match-early.html	(0/1)	0.00%	FAIL
view-transition-types-match-late-mutation.html	(0/1)	0.00%	FAIL
view-transition-types-matches-case-sensitive.html	(0/1)	0.00%	FAIL
view-transition-types-matches.html	(0/1)	0.00%	FAIL
view-transition-types-removed.html	(1/1)	100.00%	PASS
view-transition-types-reserved-mutation.html	(0/1)	0.00%	FAIL
view-transition-types-reserved.html	(0/1)	0.00%	FAIL
view-transition-types-stay.html	(0/1)	0.00%	FAIL
view-transition-waituntil-animation-manipulation.html	(0/1)	0.00%	FAIL
web-animations-api-parse-pseudo-argument.html	(0/1)	0.00%	FAIL
web-animations-api.html	(0/1)	0.00%	FAIL
writing-mode-container-resize.html	(0/1)	0.00%	FAIL