Source code

Revision control

Copy as Markdown

Other Tools

Test Info:

<!DOCTYPE html>
<style>
* {
margin-top: 100px;
padding-left: 100px;
position: sticky;
bottom: 0px;
}
</style>
<select id="select1" multiple="multiple" style="writing-mode: vertical-rl">
<optgroup id="optgroup">text</optgroup>
</select>
<select id="select2" >text</select>
<script>
document.body.offsetTop;
select2.add(optgroup);
document.body.offsetTop;
select1.length = 1;
</script>