css/css-scrollbars/scrollbar-width-keywords.html

<!DOCTYPE html>
<meta charset="UTF-8">
<link rel="author" title="Xidorn Quan" href="mailto:me@upsuper.org">
<link rel="author" title="Mozilla" href="https://www.mozilla.org">
<link rel="help" href="https://drafts.csswg.org/css-scrollbars-1/#scrollbar-width">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  .area {
    width: 100px;
    height: 100px;
    overflow: auto;
    display: inline-block;
  }
  .area::before {
    content: "";
    display: block;
    width: 200px;
    height: 200px;
  }
</style>
<div id="scrollbar-none" class="area" style="scrollbar-width: none"></div>
<div id="scrollbar-thin" class="area" style="scrollbar-width: thin"></div>
<div id="scrollbar-auto" class="area" style="scrollbar-width: auto"></div>
<script>
test(function() {
  let elem = document.getElementById("scrollbar-none");
  assert_equals(elem.clientWidth, 100);
  assert_equals(elem.clientHeight, 100);
}, "scrollbar-width: none should have no scrollbar");

test(function() {
  let thin = document.getElementById("scrollbar-thin");
  let auto = document.getElementById("scrollbar-auto");
  assert_greater_than_equal(thin.clientWidth, auto.clientWidth);
  assert_greater_than_equal(thin.clientHeight, auto.clientHeight);
}, "scrollbar-width: thin should have scrollbar no wider than auto");
</script>