<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title> CSS Scroll Snap 2 Test: scroll-start interaction with scroll-snap</title>
<link rel="help" href="https://drafts.csswg.org/css-scroll-snap-2/#scroll-start">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body>
<style>
body {
margin: 0px;
}
.spacer {
height: 200px;
width: 100px;
}
.scroller {
height: 220px;
width: 100px;
overflow: scroll;
scroll-snap-type: both mandatory;
}
#single_snap_scroller {
scroll-start: 100%;
}
#multi_snap_scroller {
scroll-start: 350px;
}
.snap_point {
width: 100px;
height: 200px;
scroll-snap-align: start;
}
</style>
<div id="single_snap_scroller" class="scroller">
<div id="top_spacer" class="spacer"></div>
<div id="lone_snap_point" class="snap_point"></div>
<div id="bottom_spacer" class="spacer"></div>
</div>
<div id="multi_snap_scroller" class="scroller">
<div id="snap_point_1" class="snap_point"></div>
<div id="snap_point_2" class="snap_point"></div>
<div id="snap_point_3" class="snap_point"></div>
</div>
<script>
test((t) => {
assert_equals(single_snap_scroller.scrollTop,
top_spacer.getBoundingClientRect().height,
"scroller snaps to top of snap point");
}, "snap overrides scroll-start position");
test((t) => {
// scroll-start sets the initial scroll offset to 350px which is closer to
// the third snap point than the second, so the scroller should snap to
// the third snap_point.
assert_equals(multi_snap_scroller.scrollTop,
multi_snap_scroller.scrollHeight - multi_snap_scroller.clientHeight,
"scroller snaps to snap point closer to start position.");
}, "scroller snaps based on scroll-start position");
</script>
</body>
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