css/cssom-view/pt-to-px-width.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>10pt converted to offset/client/scroll width</title>
<link rel="help" href="https://www.w3.org/TR/css-values-4/#absolute-lengths">

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
/* According to the CSS Values specification 10pt is abour 13.33px. */
#target { width: 10pt; }
</style>

<div id="target"></div>

<script>
test(() => {
  assert_equals(target.scrollWidth, 13, "scrollWidth");
  assert_equals(target.offsetWidth, 13, "offsetWidth");
  assert_equals(target.clientWidth, 13, "clientWidth");
});
</script>