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firefox/testing/web-platform/tests/css/css-anchor-position/at-position-try-invalidation-shadow-dom.html
Daniel Baumann 5e9a113729
Adding upstream version 140.0.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-25 09:37:52 +02:00

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HTML

<!DOCTYPE html>
<title>CSS Anchor Positioning Test: Dynamically change @position-try rules in Shadow DOM</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#fallback-rule">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
body { margin: 0; }
#host { width: 200px }
</style>
<div id="host">
<template shadowrootmode="open">
<style>
::slotted(#slotted), :host {
position-try-fallbacks: --pf;
position: absolute;
left: 999999px; /* force fallback */
}
</style>
<slot></slot>
</template>
<div id="slotted"></div>
</div>
<script>
test(() => {
assert_equals(host.offsetLeft, 999999);
}, "#host is initially left: 999999px");
test(() => {
assert_equals(slotted.offsetLeft, 999999);
}, "#slotted is initially left: 999999px");
host.shadowRoot.styleSheets[0].insertRule(`
@position-try --pf { left: 100px; }
`);
test(() => {
assert_equals(host.offsetLeft, 100);
}, "#host with inserted @position-try applied");
test(() => {
assert_equals(slotted.offsetLeft, 100);
}, "#slotted with inserted @position-try applied");
</script>