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<!doctype HTML>
<meta charset=utf8>
<title>CSS Content Visibility: auto not skipped, but skipped after change of positioned-element style</title>
<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#anchor-relevance">
<script src="/web-animations/testcommon.js"></script>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
#anchor, #positioned {
width: 200px;
height: 200px;
}
#lock {
height: 400px;
width: 400px;
content-visibility: auto;
border: 1px solid black;
}
pre {
position: relative;
top: 200px;
}
#container {
position:relative;
height: 10000px;
}
#anchor {
anchor-name: --anchor;
background-color: lightblue;
}
#anchor2 {
anchor-name: --anchor2;
}
#positioned {
position: absolute;
background-color: lightgreen;
left: anchor(right);
top: anchor( --anchor2 top);
}
</style>
<div id=container>
<div id=lock>
<div id=anchor></div>
<div>
<div id=anchor2></div>
</div>
</div>
<div id=positioned></div>
</div>
<pre id=output>
</pre>
<script>
"use strict";
let skipped = false;
lock.addEventListener("contentvisibilityautostatechange",
(e) => {
skipped = e.skipped;
});
promise_test(async t => {
positioned.style.positionAnchor = "--anchor";
await waitForAnimationFrames(2);
assert_equals(positioned.getBoundingClientRect().left, 209,
'#positioned should be anchored because #anchor is on-screen.');
window.scrollTo(0, 10000);
await waitForAnimationFrames(2);
assert_equals(positioned.getBoundingClientRect().left, 209,
'#positioned should be anchored because it was anchored to #anchor before #anchor was scrolled offscreen, so #anchor does not become skipped.');
assert_false(skipped, "The content-visibility subtree is not skipped despite being offscreen.");
positioned.style.position = "static";
await waitForAnimationFrames(2);
assert_true(skipped, "The content-visibility subtree is now skipped.");
});
</script>
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