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<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
#space { height: 4000px; }
#ancestor { position: relative; }
#before, #anchor { height: 100px; }
#anchor { background-color: green; }
.layout1 { padding-top: 20px; }
.layout2 { margin-right: 20px; }
.layout3 { max-width: 100px; }
.layout4 { min-height: 400px; }
.layout5 { position: static !important; }
.layout6 { left: 20px; }
.layout7 { transform: matrix(1, 0, 0, 1, 50, 50); }
.nonLayout1 { color: red; }
.nonLayout2 { font-size: 200%; }
.nonLayout3 { box-shadow: 10px 10px 10px gray; }
.nonLayout4 { opacity: 0.5; }
.nonLayout5 { z-index: -1; }
.scroller {
overflow: scroll;
width: 600px;
height: 600px;
}
</style>
<div id="maybeScroller">
<div id="space">
<div id="ancestor">
<div id="before"></div>
<div id="anchor"></div>
</div>
</div>
</div>
<script>
// Tests that scroll anchoring is suppressed when one of the "layout-affecting"
// properties is modified on an ancestor of the anchor node.
var scroller;
var ancestor = document.querySelector("#ancestor");
var before = document.querySelector("#before");
function runCase(classToApply, expectSuppression) {
// Reset.
scroller.scrollTop = 0;
ancestor.className = "";
before.style.height = "";
scroller.scrollTop = 150;
ancestor.className = classToApply;
before.style.height = "150px";
var expectedTop = expectSuppression ? 150 : 200;
assert_equals(scroller.scrollTop, expectedTop);
}
function runAll() {
for (var i = 1; i <= 7; i++)
runCase("layout" + i, true);
for (var i = 1; i <= 5; i++)
runCase("nonLayout" + i, false);
}
test(() => {
document.querySelector("#maybeScroller").className = "";
scroller = document.scrollingElement;
runAll();
}, "Ancestor changes in document scroller.");
test(() => {
scroller = document.querySelector("#maybeScroller");
scroller.className = "scroller";
runAll();
}, "Ancestor changes in scrollable <div>.");
</script>
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