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<!DOCTYPE html>
<title>Layout Instability: off-screen content-visibility:auto content</title>
<link rel="help" href="https://wicg.github.io/layout-instability/" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="resources/util.js"></script>
<script>
// These scripts need to be before the contents because we need to ensure no
// layout shifts during page load.
promise_test(async () => {
const watcher = new ScoreWatcher;
// Wait for the initial render to complete.
await waitForAnimationFrames(2);
window.scrollTo(0, 100000 + 100);
await waitForAnimationFrames(2);
assert_equals(watcher.score, 0);
// This should report a layout shift as target is now visible.
target.style.top = '100100px';
await watcher.promise;
const expectedScore = computeExpectedScore(100 * 100, 1);
assert_approx_equals(watcher.score, expectedScore, 1e-8, "before scroll to top");
// No new layout shift should be reported when target is scrolled out of screen.
window.scrollTo(0, 0);
await waitForAnimationFrames(2);
assert_approx_equals(watcher.score, expectedScore, 1e-8, "after scroll to top");
}, 'off-screen content-visibility:auto');
</script>
<style>
.auto {
content-visibility: auto;
contain-intrinsic-size: 1px;
width: 100px;
}
</style>
<div class=auto>
<div style="width: 100px; height: 100px; background: blue"></div>
</div>
<div id="target" class=auto style="position: relative; top: 100000px">
<div style="width: 100px; height: 100px; background: blue"></div>
</div>
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