<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-scroll-snap/#scroll-snap-stop" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
div {
position: absolute;
}
#scroller {
width: 400px;
height: 400px;
overflow: scroll;
scroll-snap-type: both mandatory;
}
#space {
left: 0px;
top: 0px;
width: 2100px;
height: 2100px;
}
.target {
width: 50px;
height: 50px;
scroll-snap-align: start;
}
.origin {
left: 0px;
top: 0px;
}
.always-stop {
left: 100px;
top: 0px;
scroll-snap-stop: always;
}
.closer {
left: 200px;
top: 0px;
}
</style>
<div id="scroller">
<div id="space"></div>
<div class="target origin"></div>
<div class="target always-stop"></div>
<div class="target closer"></div>
</div>
<script>
var scroller = document.getElementById("scroller");
test(() => {
scroller.scrollTo(0, 0);
assert_equals(scroller.scrollLeft, 0);
assert_equals(scroller.scrollTop, 0);
scroller.scrollBy(300, 0);
assert_equals(scroller.scrollLeft, 100);
assert_equals(scroller.scrollTop, 0);
}, "A scroll with intended direction and end position should not pass a snap " +
"area with scroll-snap-stop: always.")
test(() => {
scroller.scrollTo(0, 0);
assert_equals(scroller.scrollLeft, 0);
assert_equals(scroller.scrollTop, 0);
scroller.scrollTo(300, 0);
assert_equals(scroller.scrollLeft, 200);
assert_equals(scroller.scrollTop, 0);
}, "A scroll with intended end position should always choose the closest snap " +
"position regardless of the scroll-snap-stop value.")
// Tests for programmatic scrolls beyond the scroller bounds.
test(() => {
scroller.scrollTo(0, 0);
assert_equals(scroller.scrollLeft, 0);
assert_equals(scroller.scrollTop, 0);
scroller.scrollBy(100000, 0);
assert_equals(scroller.scrollLeft, 100);
assert_equals(scroller.scrollTop, 0);
}, "A scroll outside bounds in the snapping axis with intended direction and " +
"end position should not pass a snap area with scroll-snap-stop: always.")
test(() => {
scroller.scrollTo(0, 0);
assert_equals(scroller.scrollLeft, 0);
assert_equals(scroller.scrollTop, 0);
scroller.scrollBy(300, -10);
assert_equals(scroller.scrollLeft, 100);
assert_equals(scroller.scrollTop, 0);
}, "A scroll outside bounds in the non-snapping axis with intended direction " +
"and end position should not pass a snap area with scroll-snap-stop: always.")
</script>