I managed to get it to work if you setup your post request from a file that isn’t the index.php file. And then it only works if I popout the webpage to a new tab.
index.php
<html>
<head>
<title>PHP Test</title>
</head>
<body>
<a href="newfile.php">link</a>
</body>
</html>
newfile.php
<html>
<head>
<title>PHP Test</title>
</head>
<body>
<?php echo '<p>Hello World</p>';
?>
<form method="POST" action="/formprocess.php">
<input type="text" name="name">
<input type="submit">
</form>
</body>
</html>
formprocess.php
<?php
if( isset($_POST['name']) ){
$name = $_POST["name"];
}
echo 'Hello ' . $name . '!';
?>