E cosi ?

Codice PHP:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<?php 
if (isset($_POST['pag_go'])) {
 print $_POST['pag_go']."<br/>";
} // 
 ?>
<html>
<head>
<title>Untitled</title>
</head>
<body>
<form action="#" method="post" id="form" name="form">
    <input type="text" id="pag_go" name="pag_go">
  <button type="submit" id="invia" name="invia">Invia</button>
</form>
</body>
</html>