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- This WPT test may be referenced by the following Test IDs:
- /css/css-scroll-snap/resnap-on-snap-alignment-change.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<title>
Resnap when the current snap position is no longer a valid snap target.
</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/css/css-scroll-snap/support/common.js"></script>
<style>
html {
scroll-snap-type: y mandatory;
}
body {
margin: 0;
}
.snap {
scroll-snap-align: center;
height: 100vh;
margin: 0;
}
</style>
<body onload = "runTest()">
<div id = "card1" class="snap">ONE</div>
<div id = "card2" class="snap">TWO</div>
<div id = "card3" class="snap">THREE</div>
</body>
<script type="text/javascript">
function runTest() {
promise_test(async t => {
const scroller = document.scrollingElement;
// scroll to card THREE
let expectedSnapPosition = card3.offsetTop;
scroller.scrollTo(0, expectedSnapPosition);
assert_equals(scroller.scrollTop, expectedSnapPosition,
'Aligned with card THREE before style change');
// Snap to card TWO after invalidating card THREE as a snap target.
card3.style.scrollSnapAlign = 'none center';
await waitForNextFrame();
expectedSnapPosition = card2.offsetTop;
assert_equals(scroller.scrollTop, expectedSnapPosition,
'Aligned with card TWO after style change');
}, 'Resnap when the current snap position is no longer a valid snap target');
}
</script>
</html>