<!doctype html>
<meta charset="utf-8">
<title>Tests that after making a scrolling box a containing block, dynamically-inserted abspos boxes still get positioned correctly</title>
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1735533">
<link rel="help" href="https://drafts.csswg.org/css-position/#abspos-insets">
<link rel="author" href="mailto:[email protected]" title="Emilio Cobos Álvarez">
<link rel="author" href="https://mozilla.org" title="Mozilla">
<link rel="match" href="containing-block-change-scrollframe-ref.html">
<style>
#container {
width: 400px;
height: 400px;
margin: 100px;
background-color: purple;
overflow: hidden;
}
#spacer {
height: 700px;
}
#bottom {
height: 100px;
background-color: green;
}
#abspos {
position: absolute;
width: 100px;
height: 100px;
background-color: green;
top: 400px;
left: 0;
}
</style>
<div id="container">
<div id="spacer"></div>
<div id="bottom"></div>
</div>
<script>
let container = document.getElementById("container");
container.scrollTop = 400;
container.getBoundingClientRect();
container.style.position = "relative";
container.getBoundingClientRect();
let abspos = document.createElement("div");
abspos.id = "abspos";
container.appendChild(abspos);
</script>