im developing a PHP program and im stuck and need help i have my files stored on my webhost file manager in the same folder.

i have built my PHP files so they connect to each other example

<form method="POST" action="/classes/js/test/test/test.php">
<p><strong>Logged in as | <a href="/classes/js/test/test/test.php" target="_blank">New Run</a> | <a href="/classes/js/test/test/sessionclosed.html?salir=1">LOGOUT</a></strong></p>

once LOG OUT is clicked it redirects to my sessionclosed.html that i made.

but there is a button called Buy PET <input value="Buy PET" type="submit" once button is clicked it just refreshes the page and doesn't do nothing but refresh

i need this <input value="Buy PET" type="submit" button to connect to a server and execute java script

i have a program already that is identical to the one im trying to build and once the buy pet button i clicked it preforms the action (mine doesn't)

also on the origional script once the BUY PET button is clicked this is at the bottom of page source

</pre><script type="text/javascript"><!--
if(document.getElementById('u')) document.getElementById('u').focus();

i know what .document is but i don't have the original file so i cant tell it to do what i need it to