Blitz - WPT: scrollable-containing-block-validity.html

wpt / css / css-anchor-position / scrollable-containing-block-validity.html

Data from commit:
708eb61 WPT runner: support mismatch reftests and multiple rel=match links (#665) (2026-08-09)

Subtest	Status	Message
.target 1	PASS
.target 2	FAIL	assert_equals: data-expected-width expected 200 got 100 assert_equals: data-expected-height expected 200 got 100
.target 3	PASS
.target 4	PASS

Enable JavaScript in test iframe

/css/css-anchor-position/scrollable-containing-block-validity.html

<!DOCTYPE html>
<title>Tests that finding a default anchor triggers the new scrollable containing-block.</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/">
<link rel="help" href="https://drafts.csswg.org/css-position-4/#scrollable-containing-block">
<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/12552">
<style>
.scroller {
  /* Use overflow hidden instead of scroll to mitigate scrollbar differences. */
  overflow: hidden;
  position: relative;
  width: 80px;
  height: 80px;
  margin: 10px;
  border: solid 3px;
  padding: 10px;
}

.filler {
  min-width: 180px;
  min-height: 180px;
}

.anchor {
  anchor-name: --a;
}

.target {
  position: absolute;
  inset: 0;
  place-self: stretch;
}
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/check-layout-th.js"></script>
<body onload="checkLayout('.target')">

<!-- No default anchor should use the regular containing-block. -->
<div class="scroller">
  <div class="filler"><div class="anchor"></div></div>
  <div class="target" data-expected-width="100" data-expected-height="100"></div>
</div>

<!-- A default anchor - should use the scrollable containing-block. -->
<div class="scroller">
  <div class="filler"><div class="anchor"></div></div>
  <div class="target" style="position-anchor: --a;" data-expected-width="200" data-expected-height="200"></div>
</div>

<!-- A non-valid default anchor - should use the regular containing-block. -->
<div class="scroller">
  <div class="filler"><div class="anchor"></div></div>
  <div class="target" style="position-anchor: --b;" data-expected-width="100" data-expected-height="100"></div>
</div>

<!-- Only specifying position-area - should use the regular containing-block. -->
<div class="scroller">
  <div class="filler"><div class="anchor"></div></div>
  <div class="target" style="position-area: top;" data-expected-width="100" data-expected-height="100"></div>
</div>