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WPT

This page compares scores on the Web Platform Tests across web engines, using the latest master runs from wpt.fyi and Blitz's own test runner.

wpt / custom-elements

Spec: https://html.spec.whatwg.org/multipage/custom-elements.html ↗

Runs: Chrome 155.0.8039.0 (wpt@3f6b09ae3, 2026-09-03) | Firefox 157.0a1 (wpt@3f6b09ae3, 2026-09-03) | Safari 251 preview (wpt@5ce815a83, 2026-08-27) | Ladybird 1.0-795e1 (wpt@7e3d005d7, 2026-09-03) | Servo Servo 0.6 (wpt@09159dcb3, 2026-09-02) | Blitz 188486089 (wpt@a95401e4e, 2026-09-02)

Sort areas: alphabetical | by subtest count

AreaChromeFirefoxSafariLadybirdServoBlitz
Total98.8%4272/432297.8%4229/432282.1%3547/432291.2%3943/432284.3%3644/43220.0%0/4322
form-associated100.0%162/16265.4%106/16265.4%106/16263.0%102/16262.3%101/1620.0%0/162
htmlconstructor50.0%10/20100.0%20/2060.0%12/20100.0%20/20100.0%20/200.0%0/20
parser100.0%36/36100.0%36/3686.1%31/3691.7%33/3691.7%33/360.0%0/36
reactions100.0%534/53497.4%520/53462.2%332/53495.9%512/53486.1%460/5340.0%0/534
registries98.8%2426/245599.9%2453/245593.5%2296/245598.1%2408/245584.7%2080/24550.0%0/2455
state100.0%29/29100.0%29/2996.6%28/29100.0%29/2972.4%21/290.0%0/29
upgrading89.7%26/2986.2%25/2982.8%24/2986.2%25/2986.2%25/290.0%0/29
TestChromeFirefoxSafariLadybirdServoBlitz
CustomElementRegistry-constructor-and-callbacks-are-held-strongly.html5/55/55/55/55/5NOT RUN
CustomElementRegistry-getName.html4/44/42/44/44/4NOT RUN
CustomElementRegistry.html45/4646/4645/4646/4646/46NOT RUN
Document-createElement-customized-builtins.html4/44/41/43/44/4NOT RUN
Document-createElement-svg.svg2/22/22/22/20/2NOT RUN
Document-createElement.html36/3636/3636/3636/3636/36NOT RUN
Document-createElementNS-customized-builtins.html3/33/31/32/33/3NOT RUN
Document-createElementNS-prefix-timing.html3/33/33/33/32/3NOT RUN
Document-createElementNS.html4/44/44/44/44/4NOT RUN
ElementInternals-accessibility.html50/5050/5050/501/501/50NOT RUN
ElementInternals-accessibility.tentative.html3/33/30/30/30/3NOT RUN
ElementInternals-role.html68/6868/6867/680/680/68NOT RUN
HTMLElement-attachInternals.html4/44/44/44/44/4NOT RUN
HTMLElement-constructor-customized-builtins.html0/22/20/22/22/2NOT RUN
HTMLElement-constructor.html8/1212/1212/1212/1212/12NOT RUN
adopted-callback.html71/7171/7171/7117/7171/71NOT RUN
append-children-to-new-parent-cycle.htmlPASSPASSPASSERRORCRASHNOT RUN
attribute-changed-callback.html13/1313/1313/1313/1313/13NOT RUN
builtin-coverage.html444/444444/444149/444444/444444/444NOT RUN
connected-callbacks-html-fragment-parsing.html8/88/88/88/88/8NOT RUN
connected-callbacks-template.htmlPASSPASSPASSPASSPASSNOT RUN
connected-callbacks.html40/4040/4040/4016/4040/40NOT RUN
createElement-reentrant-construction.window.html2/22/22/22/22/2NOT RUN
cross-realm-callback-report-exception.html4/54/55/55/54/5NOT RUN
custom-element-reaction-queue.html6/66/66/65/66/6NOT RUN
customized-built-in-constructor-exceptions.html5/55/50/55/55/5NOT RUN
disconnected-callbacks.html40/4040/4040/4040/4040/40NOT RUN
element-internals-aria-element-reflection.html9/97/99/96/96/9NOT RUN
element-internals-behaviors.tentative.html15/151/151/151/151/15NOT RUN
element-internals-shadowroot.html7/77/77/77/77/7NOT RUN
enqueue-custom-element-callback-reactions-inside-another-callback.html8/88/88/88/88/8NOT RUN
historical.html3/33/33/33/33/3NOT RUN
microtasks-and-constructors.html5/55/55/55/55/5NOT RUN
overwritten-customElements-global.html4/44/44/44/44/4NOT RUN
perform-microtask-checkpoint-before-construction-xml-parser.xhtmlPASSPASSPASSFAILPASSNOT RUN
perform-microtask-checkpoint-before-construction.html2/22/22/22/22/2NOT RUN
prevent-extensions-crash.htmlPASSPASSPASSPASSPASSNOT RUN
pseudo-class-defined-customized-builtins.html16/1616/166/1616/1612/16NOT RUN
pseudo-class-defined-print.htmlPASSPASSNOT RUNNOT RUNNOT RUNNOT RUN
pseudo-class-defined.html24/2424/2424/2424/2418/24NOT RUN
range-and-constructors.html2/22/22/22/22/2NOT RUN
reaction-timing.html3/33/33/33/33/3NOT RUN
throw-on-dynamic-markup-insertion-counter-construct-xml-parser.xhtml11/1111/1111/1111/1111/11NOT RUN
throw-on-dynamic-markup-insertion-counter-construct.html11/1111/1111/110/1111/11NOT RUN
throw-on-dynamic-markup-insertion-counter-reactions-xml-parser.xhtml11/1111/1111/1111/1111/11NOT RUN
throw-on-dynamic-markup-insertion-counter-reactions.html11/1111/1111/110/1111/11NOT RUN
upgrading.html28/2828/2828/2828/2828/28NOT RUN
when-defined-reentry-crash.htmlPASSPASSPASSPASSPASSNOT RUN
xhtml-crash.xhtmlPASSPASSPASSPASSPASSNOT RUN