Click here to download the Blitz Browser!

Status

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

CSS PropertiesHTML ElementsEventsWPT TestsWPT History

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

wpt / css / cssom

Score history
1 month3 months6 months1 year2 years4 yearsAll time
0%20%40%60%80%100%May 2025Jul 2025Sep 2025Nov 2025Jan 2026Mar 2026May 2026Jul 2026Sep 2026css/cssom

Data from commit:
ab0e30b Give form controls a UA default font-family (#940) (2026-09-25)

AreaInterop ScoreTestsTest %SubtestsSubtest %
Total53.06%(125/290)43.10%(2996/4410)67.94%
TestSubtestsSubtest %Status
CSS-escape-numeric-id.html(2/2)100.00%PASS
CSS-namespace-object-class-string.html(0/4)0.00%FAIL
CSS-supports.html(10/11)90.91%FAIL
CSSConditionRule-conditionText.html(1/1)100.00%PASS
CSSContainerRule.tentative.html(0/2)0.00%FAIL
CSSCounterStyleRule.html(0/1)0.00%FAIL
CSSFontFaceRule.html(1/1)100.00%PASS
CSSFontFeatureValuesRule.html(0/8)0.00%FAIL
CSSGroupingRule-cssRules.html(1/1)100.00%PASS
CSSGroupingRule-insertRule-computed.html(1/1)100.00%PASS
CSSGroupingRule-insertRule.html(7/7)100.00%PASS
CSSImportRule-insertRule-styleSheet-parentStyleSheet.html(0/1)0.00%FAIL
CSSImportRule-layer-false-positive.html(0/11)0.00%TIMEOUT
CSSImportRule-layer-media.html(0/6)0.00%TIMEOUT
CSSImportRule-media-identity.html(0/1)0.00%FAIL
CSSKeyframeRule-keyText-edge-cases.html(3/14)21.43%FAIL
CSSKeyframeRule-keyText.html(4/11)36.36%FAIL
CSSKeyframeRule.html(1/2)50.00%FAIL
CSSKeyframesRule-appendRule-invalid.html(1/4)25.00%FAIL
CSSKeyframesRule-appendRule-multiple.html(0/2)0.00%FAIL
CSSKeyframesRule-deleteRule-detach.html(1/2)50.00%FAIL
CSSKeyframesRule-indexed-getter.html(4/6)66.67%FAIL
CSSKeyframesRule.html(0/2)0.00%FAIL
CSSNamespaceRule.html(1/1)100.00%PASS
CSSRule-type.html(8/14)57.14%FAIL
CSSRuleList-appendRule-keyframe-001-crash.html(1/1)100.00%PASS
CSSRuleList-appendRule-keyframe-002-crash.html(1/1)100.00%PASS
CSSRuleList.html(1/1)100.00%PASS
CSSStyleDeclaration-indexed-properties.html(0/6)0.00%FAIL
CSSStyleDeclaration-iterator.html(0/1)0.00%FAIL
CSSStyleRule-selectorText-setter.html(7/7)100.00%PASS
CSSStyleRule-set-selectorText-namespace.html(5/5)100.00%PASS
CSSStyleRule-set-selectorText.html(78/82)95.12%FAIL
CSSStyleRule.html(7/10)70.00%FAIL
CSSStyleSheet-constructable-baseURL.html(0/3)0.00%FAIL
CSSStyleSheet-constructable-concat.html(0/1)0.00%FAIL
CSSStyleSheet-constructable-cssRules.html(0/1)0.00%FAIL
CSSStyleSheet-constructable-disabled-regular-sheet-insertion.html(0/1)0.00%FAIL
CSSStyleSheet-constructable-disallow-import.tentative.html(0/4)0.00%FAIL
CSSStyleSheet-constructable-duplicate.html(0/4)0.00%FAIL
CSSStyleSheet-constructable-insertRule-base-uri.html(0/1)0.00%FAIL
CSSStyleSheet-constructable-invalidation.html(0/3)0.00%FAIL
CSSStyleSheet-constructable-replace-cssRules.html(0/2)0.00%FAIL
CSSStyleSheet-constructable-replace-on-regular-sheet.html(0/3)0.00%FAIL
CSSStyleSheet-constructable-replace-thenable.html(0/1)0.00%FAIL
CSSStyleSheet-constructable.html(0/32)0.00%FAIL
CSSStyleSheet-insertRule-computed.html(1/1)100.00%PASS
CSSStyleSheet-modify-after-removal.html(0/2)0.00%FAIL
CSSStyleSheet-replace-detach-old-rules.html(0/4)0.00%FAIL
CSSStyleSheet-replace-parse-errors.html(0/8)0.00%FAIL
CSSStyleSheet-template-adoption.html(0/1)0.00%FAIL
CSSStyleSheet.html(10/17)58.82%FAIL
HTMLLinkElement-disabled-001.html(0/2)0.00%SKIP
HTMLLinkElement-disabled-002.html(0/1)0.00%SKIP
HTMLLinkElement-disabled-003.html(0/1)0.00%SKIP
HTMLLinkElement-disabled-004.html(0/1)0.00%SKIP
HTMLLinkElement-disabled-005.html(0/1)0.00%SKIP
HTMLLinkElement-disabled-006.html(0/1)0.00%SKIP
HTMLLinkElement-disabled-007.html(0/1)0.00%SKIP
HTMLLinkElement-disabled-alternate.html(1/1)100.00%PASS
HTMLLinkElement-load-event-002.html(0/2)0.00%SKIP
HTMLLinkElement-load-event.html(0/1)0.00%FAIL
HTMLStyleElement-load-event.html(0/1)0.00%FAIL
MediaList-parsing.html(1/13)7.69%FAIL
MediaList.html(0/1)0.00%FAIL
MediaList2.xhtml(5/5)100.00%PASS
MutationObserver-style.html(0/2)0.00%FAIL
StyleSheet-properties.html(22/35)62.86%FAIL
StyleSheetList-constructable-shadow-with-style-recalc.html(0/1)0.00%FAIL
StyleSheetList-constructable-shadow.html(0/1)0.00%FAIL
StyleSheetList-constructable-with-style-recalc.html(0/1)0.00%FAIL
StyleSheetList-constructable.html(0/1)0.00%FAIL
StyleSheetList.html(1/1)100.00%PASS
adoptedstylesheets-adopt-link.tentative.html(0/1)0.00%FAIL
adoptedstylesheets-adopt-style-subresource.tentative.html(0/1)0.00%FAIL
adoptedstylesheets-adopt-style.tentative.html(0/1)0.00%FAIL
adoptedstylesheets-cascade-order.html(0/13)0.00%FAIL
adoptedstylesheets-invalid-assignment-crash.html(1/1)100.00%PASS
adoptedstylesheets-modify-array-and-sheet.html(0/3)0.00%FAIL
adoptedstylesheets-observablearray.html(0/5)0.00%FAIL
all-initial-csstext.html(1/1)100.00%PASS
at-namespace.html(1/1)100.00%PASS
base-uri.html(0/3)0.00%FAIL
border-shorthand-serialization.html(3/3)100.00%PASS
caretPositionFromPoint-audioVideo.html(0/2)0.00%FAIL
caretPositionFromPoint-in-flex-container.html(0/3)0.00%FAIL
caretPositionFromPoint-with-transformation.html(0/1)0.00%SKIP
caretPositionFromPoint.html(0/7)0.00%FAIL
caretRangeFromPoint-replace-document.tentative.html(0/1)0.00%FAIL
caretRangeFromPoint-textarea-transform.tentative.html(0/2)0.00%FAIL
caretRangeFromPoint.tentative.html(0/8)0.00%FAIL
change-rule-with-layers-crash.html(1/1)100.00%PASS
computed-style-001.html(3/4)75.00%FAIL
computed-style-002.html(0/1)0.00%FAIL
computed-style-003.html(0/1)0.00%FAIL
computed-style-004.html(0/2)0.00%FAIL
computed-style-005.html(4/4)100.00%PASS
computed-style-set-property.html(0/5)0.00%FAIL
css-rule-selector-text.html(2/2)100.00%PASS
css-style-attr-decl-block.html(4/7)57.14%FAIL
css-style-attribute-modifications.html(1/1)100.00%PASS
css-style-declaration-modifications.html(4/4)100.00%PASS
css-style-reparse.html(1/2)50.00%FAIL
cssimportrule-parent.html(0/1)0.00%FAIL
cssimportrule-sheet-identity.html(0/1)0.00%FAIL
cssimportrule.html(6/11)54.55%FAIL
cssom-cssText-serialize.html(1/1)100.00%PASS
cssom-cssstyledeclaration-set.html(1/1)100.00%PASS
cssom-fontfacerule-constructors.html(0/2)0.00%FAIL
cssom-fontfacerule.html(1/1)100.00%PASS
cssom-getPropertyValue-common-checks.html(11/11)100.00%PASS
cssom-pagerule.html(0/22)0.00%FAIL
cssom-ruleTypeAndOrder.html(6/7)85.71%FAIL
cssom-setProperty-shorthand.html(76/76)100.00%PASS
cssstyledeclaration-all-shorthand.html(21/27)77.78%FAIL
cssstyledeclaration-cssfontrule.tentative.html(0/1)0.00%FAIL
cssstyledeclaration-csstext-all-shorthand.html(6/6)100.00%PASS
cssstyledeclaration-csstext-final-delimiter.html(3/3)100.00%PASS
cssstyledeclaration-csstext-important.html(1/1)100.00%PASS
cssstyledeclaration-csstext-setter.window.html(9/9)100.00%PASS
cssstyledeclaration-csstext.html(11/11)100.00%PASS
cssstyledeclaration-custom-properties.html(0/1)0.00%FAIL
cssstyledeclaration-mutability.html(2/3)66.67%FAIL
cssstyledeclaration-mutationrecord-001.html(0/1)0.00%FAIL
cssstyledeclaration-mutationrecord-002.html(0/1)0.00%FAIL
cssstyledeclaration-mutationrecord-003.html(0/1)0.00%FAIL
cssstyledeclaration-mutationrecord-004.html(0/1)0.00%FAIL
cssstyledeclaration-mutationrecord-005.html(0/1)0.00%FAIL
cssstyledeclaration-nested.html(0/1)0.00%FAIL
cssstyledeclaration-properties.html(0/1)0.00%FAIL
cssstyledeclaration-registered-custom-properties.html(0/2)0.00%FAIL
cssstyledeclaration-removeProperty-all.html(1/2)50.00%FAIL
cssstyledeclaration-setter-attr.html(2/2)100.00%PASS
cssstyledeclaration-setter-declarations.html(0/4)0.00%FAIL
cssstyledeclaration-setter-form-controls.html(8/8)100.00%PASS
cssstyledeclaration-setter-logical.html(0/1)0.00%FAIL
declaration-block-all-crash.html(1/1)100.00%PASS
delete-namespace-rule-when-child-rule-exists.html(1/1)100.00%PASS
escape.html(9/10)90.00%FAIL
flex-serialization.html(4/5)80.00%FAIL
font-family-serialization-001.html(22/27)81.48%FAIL
font-shorthand-serialization.html(1/1)100.00%PASS
font-variant-shorthand-serialization.html(6/7)85.71%FAIL
functional-values-comma.html(7/7)100.00%PASS
getComputedStyle-animations-replaced-into-ib-split.html(1/1)100.00%PASS
getComputedStyle-basic.html(2/4)50.00%FAIL
getComputedStyle-calc.html(5/5)100.00%PASS
getComputedStyle-detached-subtree.html(0/6)0.00%FAIL
getComputedStyle-display-none-001.html(1/2)50.00%FAIL
getComputedStyle-display-none-002.html(1/1)100.00%PASS
getComputedStyle-display-none-003.html(1/1)100.00%PASS
getComputedStyle-display-none-shadow-invalidation.html(0/2)0.00%FAIL
getComputedStyle-dynamic-subdoc.html(0/1)0.00%FAIL
getComputedStyle-getter-v-properties.tentative.html(10/10)100.00%PASS
getComputedStyle-important.html(2/2)100.00%PASS
getComputedStyle-insets-absolute-crash.html(1/1)100.00%PASS
getComputedStyle-insets-absolute-logical-crash.html(1/1)100.00%PASS
getComputedStyle-insets-absolute-roundtrip.html(4/4)100.00%PASS
getComputedStyle-insets-absolute.html(108/324)33.33%FAIL
getComputedStyle-insets-fixed.html(108/324)33.33%FAIL
getComputedStyle-insets-grid.html(0/1)0.00%FAIL
getComputedStyle-insets-multicol-absolute-crash.html(1/1)100.00%PASS
getComputedStyle-insets-nobox.html(216/216)100.00%PASS
getComputedStyle-insets-relative.html(252/252)100.00%PASS
getComputedStyle-insets-relpos-inline.html(0/4)0.00%FAIL
getComputedStyle-insets-static.html(216/216)100.00%PASS
getComputedStyle-insets-sticky-container-for-abspos.html(180/252)71.43%FAIL
getComputedStyle-insets-sticky.html(180/252)71.43%FAIL
getComputedStyle-layout-dependent-removed-ib-sibling.html(1/1)100.00%PASS
getComputedStyle-layout-dependent-replaced-into-ib-split.html(1/1)100.00%PASS
getComputedStyle-line-height.html(4/4)100.00%PASS
getComputedStyle-live.html(1/1)100.00%PASS
getComputedStyle-logical-enumeration.html(1/1)100.00%PASS
getComputedStyle-margins-roundtrip.html(4/4)100.00%PASS
getComputedStyle-math-function-percentage.html(12/12)100.00%PASS
getComputedStyle-mutations.html(6/9)66.67%FAIL
getComputedStyle-page-rule.xhtml(1/1)100.00%PASS
getComputedStyle-pointerEvents.html(3/3)100.00%PASS
getComputedStyle-property-order.html(0/1)0.00%FAIL
getComputedStyle-pseudo-checkmark.html(1/3)33.33%FAIL
getComputedStyle-pseudo-class.html(1/1)100.00%PASS
getComputedStyle-pseudo-picker-icon.html(1/3)33.33%FAIL
getComputedStyle-pseudo-picker.html(1/9)11.11%FAIL
getComputedStyle-pseudo-shadow.html(0/2)0.00%FAIL
getComputedStyle-pseudo-with-argument.html(0/22)0.00%FAIL
getComputedStyle-pseudo.html(1/28)3.57%FAIL
getComputedStyle-resolved-colors.html(13/13)100.00%PASS
getComputedStyle-resolved-min-max-clamping.html(0/1)0.00%FAIL
getComputedStyle-resolved-min-size-auto.html(16/16)100.00%PASS
getComputedStyle-root-variables.html(1/1)100.00%PASS
getComputedStyle-root.html(1/1)100.00%PASS
getComputedStyle-shadow-host.html(0/1)0.00%FAIL
getComputedStyle-shadow-inherit.html(0/2)0.00%FAIL
getComputedStyle-special-chars-crash.html(1/1)100.00%PASS
getComputedStyle-sticky-pos-percent.html(0/1)0.00%FAIL
getComputedStyle-style-element-updates.html(4/4)100.00%PASS
getComputedStyle-visibility-nominal-case.html(2/2)100.00%PASS
getComputedStyle-visibility-override.html(2/2)100.00%PASS
getComputedStyle-visibility-unset.html(2/2)100.00%PASS
getComputedStyle-width-scroll.tentative.html(1/1)100.00%PASS
grouping-rule-no-nested-declarations.html(5/5)100.00%PASS
historical.html(13/20)65.00%FAIL
idlharness.html(223/497)44.87%FAIL
import-namespace-invalid-prelude.html(8/8)100.00%PASS
inline-style-001.html(3/5)60.00%FAIL
insert-dir-rule-crash.html(1/1)100.00%PASS
insert-dir-rule-in-iframe-crash.html(1/1)100.00%PASS
insert-invalid-where-rule-crash.html(1/1)100.00%PASS
insertRule-across-context.html(0/2)0.00%FAIL
insertRule-charset-no-index.html(2/2)100.00%PASS
insertRule-font-face.html(1/1)100.00%PASS
insertRule-from-script.html(1/1)100.00%PASS
insertRule-import-no-index.html(2/2)100.00%PASS
insertRule-import-no-sheet-crash.html(1/1)100.00%PASS
insertRule-import-trailing-garbage-crash.html(1/1)100.00%PASS
insertRule-namespace-after-import.html(2/2)100.00%PASS
insertRule-namespace-no-index.html(3/3)100.00%PASS
insertRule-no-index.html(2/2)100.00%PASS
insertRule-syntax-error-01.html(1/1)100.00%PASS
invalid-pseudo-elements.html(1/1)100.00%PASS
link-element-stylesheet-title.html(0/2)0.00%FAIL
medialist-appendmedium-parse-single-and-dedup.html(0/3)0.00%FAIL
medialist-deletemedium-parse-and-remove-all.html(0/2)0.00%FAIL
medialist-dynamic-001.html(0/1)0.00%FAIL
medialist-interfaces-001.html(0/4)0.00%FAIL
medialist-interfaces-002.html(1/3)33.33%FAIL
medialist-interfaces-004.html(0/2)0.00%FAIL
mediaquery-sort-dedup.html(0/2)0.00%FAIL
nested-import-namespace-invalid.html(3/4)75.00%FAIL
overflow-serialization.html(10/10)100.00%PASS
page-descriptors.html(0/21)0.00%FAIL
preferred-stylesheet-order.html(0/1)0.00%FAIL
preferred-stylesheet-reversed-order.html(0/1)0.00%FAIL
property-accessors.html(0/9)0.00%FAIL
removerule-invalidation-crash.html(1/1)100.00%PASS
resolved-border-width.html(2/2)100.00%PASS
rule-restrictions.html(0/2)0.00%FAIL
selectorSerialize.html(23/23)100.00%PASS
selectorText-modification-restyle-001.html(1/1)100.00%PASS
selectorText-modification-restyle-002.html(0/2)0.00%FAIL
serialization-CSSDeclaration-with-important.html(4/4)100.00%PASS
serialize-all-longhands.html(1/2)50.00%FAIL
serialize-custom-props.html(20/20)100.00%PASS
serialize-media-rule.html(11/12)91.67%FAIL
serialize-namespaced-type-selectors.html(60/60)100.00%PASS
serialize-values.html(672/697)96.41%FAIL
serialize-variable-reference.html(4/4)100.00%PASS
serialize-whitespace.html(1/1)100.00%PASS
set-selector-text-attachment.html(1/1)100.00%PASS
set-selector-text-detached-rule-delete-crash.html(1/1)100.00%PASS
set-selector-text-detached-rule-replace-crash.html(1/1)100.00%PASS
setproperty-null-undefined.html(3/4)75.00%FAIL
shadow-dom-style-sheet.html(0/3)0.00%FAIL
shorthand-serialization.html(7/7)100.00%PASS
shorthand-values.html(20/21)95.24%PASS
style-attr-clone.html(1/1)100.00%PASS
style-attr-update-across-documents.html(0/1)0.00%SKIP
style-background-position-longhands.html(3/3)100.00%PASS
style-background-position.html(7/7)100.00%PASS
style-background-repeat.html(3/3)100.00%PASS
style-background-shorthand-overwrite.html(4/4)100.00%PASS
style-backgroundcolor-oklch.html(1/1)100.00%PASS
style-backgroundcolor-table-row.html(1/1)100.00%PASS
style-backgroundimage-lineargradient.html(1/1)100.00%PASS
style-border-shorthand-var.html(1/1)100.00%PASS
style-color-values.html(6/6)100.00%PASS
style-color.html(4/4)100.00%PASS
style-cssText-mutations.html(1/4)25.00%FAIL
style-element-inline-important.html(0/1)0.00%FAIL
style-element-insertion-removal-computed.html(2/2)100.00%PASS
style-font-shorthand.html(1/1)100.00%PASS
style-global-variable.html(1/1)100.00%PASS
style-set-cssText.html(3/3)100.00%PASS
style-set-custom-property-priority.html(0/3)0.00%FAIL
style-set-custom-property.html(0/1)0.00%FAIL
style-set-property.html(18/21)85.71%FAIL
style-sheet-interfaces-001.html(5/7)71.43%FAIL
style-sheet-interfaces-002.html(2/2)100.00%PASS
style-width-calc-vh-vw.html(1/1)100.00%PASS
stylesheet-cross-origin-redirect-quirks.sub.html(0/4)0.00%FAIL
stylesheet-replacedata-dynamic.html(0/1)0.00%FAIL
stylesheet-same-origin.sub.html(0/7)0.00%CRASH
stylesheet-title.html(0/2)0.00%FAIL
system-color-inherit.html(2/2)100.00%PASS
system-color-lowercase.html(4/4)100.00%PASS
ttwf-cssom-doc-ext-load-count.html(0/3)0.00%SKIP
ttwf-cssom-doc-ext-load-tree-order.html(1/6)16.67%FAIL
ttwf-cssom-document-extension.html(1/1)100.00%PASS
variable-names.html(0/6)0.00%FAIL
xml-stylesheet-pi-in-doctype.xhtml(1/1)100.00%PASS