Source code

Revision control

Copy as Markdown

Other Tools

Test Info:

<!DOCTYPE html>
<title>position:sticky elements should respect an overflow:hidden ancestor</title>
<meta name="assert" content="This test checks that position:sticky elements adhere to an overflow:hidden ancestor" />
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../resources/sticky-util.js"></script>
<body></body>
<script>
test(() => {
const outer_scroller = document.createElement('div');
outer_scroller.style.width = '100px';
outer_scroller.style.height = '100px';
outer_scroller.style.overflow = 'scroll';
const inner_scroller = document.createElement('div');
inner_scroller.style.width = '80%';
inner_scroller.style.height = '200px';
inner_scroller.style.overflow = 'hidden';
const sticky = document.createElement('div');
sticky.style.width = '20px';
sticky.style.height = '20px';
sticky.style.position = 'sticky';
sticky.style.top = '0';
sticky.style.background = 'red';
const spacer = document.createElement('div');
spacer.style.height = '500px';
inner_scroller.appendChild(sticky);
inner_scroller.appendChild(spacer);
outer_scroller.appendChild(inner_scroller);
document.body.appendChild(outer_scroller);
outer_scroller.scrollTop = 50;
// The sticky should attach to the inner scroller, and so should not stick.
assert_equals(sticky.offsetTop, inner_scroller.offsetTop);
}, 'A sticky element should attach to an overflow:hidden ancestor');
// This tests a specific bug in Firefox where the sticky element incorrectly
// started sticking when inside a table. See https://bugzilla.mozilla.org/show_bug.cgi?id=1488810
test(() => {
const outer_scroller = document.createElement('div');
outer_scroller.style.width = '100px';
outer_scroller.style.height = '100px';
outer_scroller.style.overflow = 'scroll';
const table = document.createElement('div');
table.style.display = 'table';
const tr = document.createElement('div');
tr.style.display = 'table-row';
const inner_scroller = document.createElement('div');
inner_scroller.style.display = 'table-cell';
inner_scroller.style.overflow = 'hidden';
const sticky = document.createElement('div');
sticky.style.width = '20px';
sticky.style.height = '20px';
sticky.style.position = 'sticky';
sticky.style.top = '0';
sticky.style.background = 'red';
const spacer = document.createElement('div');
spacer.style.height = '500px';
inner_scroller.appendChild(sticky);
inner_scroller.appendChild(spacer);
tr.append(inner_scroller);
table.appendChild(tr);
outer_scroller.appendChild(table);
document.body.appendChild(outer_scroller);
outer_scroller.scrollTop = 50;
// The sticky should attach to the inner scroller, and so should not stick.
assert_equals(sticky.offsetTop, inner_scroller.offsetTop);
}, 'A sticky element should attach to an overflow:hidden ancestor inside a table');
</script>