The first page of the application passes a value over to the next page using a text box. If the user isn't logged in then it will display a login link that will allow them to do so. Whenever they click the link the page will refresh which drops the value for the variable passed over from the first page.
This is the code for the input box on the first page (HTML)
<form action="verify.php" METHOD=post>
Enter a School:
<input type="text" name="school" />
<INPUT TYPE=SUBMIT VALUE="GO">
</form>
This is the code for the second page to check if they are logged in or not (PHP)
$user = $facebook->getUser();
if ($user == 0){
$loginUrl = $facebook->getLoginUrl();
echo ( '<b>Please <a href="'.$loginUrl.'">Login</a> before proceeding.</b>' );
echo ( '<br />' );