im making a google extention but when i try to display some data it just shows the base code
html code to transfer the data
<form action="/assinmenttracker.php", method="post">
<br>
<br>
Name: <input type="text" name="fname"><br><br>
<input type="submit" value="Submit">
and the PHP code
<html>
<body>
Welcome <?php echo $_POST["fname"]; ?><br>
</body>
</html>