<html>
<head>
<title>Popup Blocked Post Blank</title>
<script>
function test() {
  // We rely on sequential ordering of POST processing.
  var form = document.getElementById('form');
  form.submit();
}
</script>
</head>
<body onload="test()">
If the POST pop-up was not blocked then there will be an warning message displayed in a new tab. Otherwise, the test passes.
<form id="form" method="post" action="data:text/html,<title>Popup Success!</title>you should not see this message if popup blocker is enabled" target="_blank">
<input type="submit" value="Submit to new window"/>
</form>
</body>
</html>