<!DOCTYPE html>
<meta charset="utf-8" />
<title>Popover element appearance</title>
<link rel="author" href="mailto:masonf@chromium.org">
<link rel=help href="https://open-ui.org/components/popover.research.explainer">
<link rel=help href="https://html.spec.whatwg.org/multipage/popover.html">
<link rel="match" href="popover-appearance-ref.html">

<style>
[popover] {top: 100px; bottom: auto;}
[popover=""] {left: -300px}
[popover=auto] {left: -100px; }
[popover=manual] {left: 100px; }
[popover=invalid] {left: 300px; }
</style>

<p>There should be four popovers with similar appearance.</p>
<div popover>Blank
  <div popover=auto>Auto</div>
</div>
<div popover=manual>Manual</div>
<!-- This ensures unsupported popover values are treated as popover=manual -->
<div popover=invalid>Invalid</div>
<script>
  document.querySelectorAll('[popover]').forEach(p => p.showPopover());
</script>
