Well, I don't want to start getting too involved. I don't think this is that serious of a problem.
Essentially, the fact that you are 'scanning' a .php file makes things tricky. My script opens up that php file, and it sees exactly what you just pasted. So it does not get a single Address, as your 'show_users.php' code is never run(which opens the database and writes out the address).
If you open the file in a web browser, the code is executed, and we get adresses printed on the screen. But when you open the file up(binary)(meaning, in a text editor, or such), then we see the actual code. So my script is searching this text for an address:
include ($_SERVER['DOCUMENT_ROOT'] . "/connect.php");
die('Could not connect: ' . mysql_error());
}mysql_select_db("bindslevdesigns_com", $con);$result = mysql_query("SELECT * FROM club_new_user");while($row = mysql_fetch_array($result))
echo "<br />";
My script opens the file, and that is indeed what is in the file. I guess for this to work, you would have to be comparing a file other than a PHP document. Meaning, you would have to slightly alter your PHP code, so that it creates a new, temporary html file, and redirects you to it. Then you would simply be comparing your xml file to the newly created .html file.
Only one more complication I see with my idea though, and that would be, the .php file would have to be loaded to update the .html file. Either that, or you convert to an AJAX solution(makes more work). An AJAX solution would be completely ideal, as you would load an HTML file, and this file could execute some PHP files on your server, while still remaining on the same page. And using the proper event handlers, you could have it execute my compare script after it has run the show_users.php file.
I suppose you might not know much about AJAX, and so I would need to implement a solution for you. I can do this, but you would have to allow me time. I have projects of my own I'm working on, and to perfect my solution to your problem, I would need a bit of time to work on all the code and make sure it will work.