<!DOCTYPE html>
<title>Tests position fallback with scrollers with mixed writing modes</title>
<link rel="author" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#scroll">
<link rel="help" href="https://drafts.csswg.org/css-anchor-1/#fallback-apply">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/test-common.js"></script>
<style>
body {
margin: 0;
}
#vrl-scroller {
writing-mode: vertical-rl;
overflow-x: scroll;
width: calc(100vw - 90px);
height: 400px;
outline: 1px solid black;
}
#anchor {
anchor-name: --a;
width: 100px;
height: 100px;
margin-left: 1000px;
background: orange;
}
#anchored {
position: fixed;
width: 100px;
height: 100px;
background: green;
position-anchor: --a;
position-try-fallbacks: --pf1, --pf2;
/* Top of the anchor */
bottom: anchor(top);
left: anchor(left);
}
@position-try --pf1 {
/* Bottom of the anchor */
top: anchor(bottom);
bottom: auto;
}
@position-try --pf2 {
/* Left of the anchor */
top: anchor(top);
right: anchor(left);
bottom: auto;
left: auto;
}
</style>
<div style="height: 200px"></div>
<div id="vrl-scroller">
<div id="anchor"></div>
</div>
<div style="height: 1000px"></div>
<div id="anchored"></div>
<script>
promise_test(async () => {
await waitUntilNextAnimationFrame();
assert_fallback_position(anchored, anchor, 'top');
}, 'Should use the first fallback position at the initial scroll offsets');
promise_test(async () => {
document.documentElement.scrollTop = 101;
await waitUntilNextAnimationFrame();
assert_fallback_position(anchored, anchor, 'bottom');
}, 'Should use the second fallback position after scrolling viewport down');
promise_test(async () => {
let vrlScroller = document.getElementById('vrl-scroller');
vrlScroller.scrollLeft = -100;
await waitUntilNextAnimationFrame();
assert_fallback_position(anchored, anchor, 'left');
}, 'Should use the third fallback position after scrolling the vrl scroller left');
</script>
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