Troubles with substr (PHP)

[MrApples]

I've been having a load of trouble with the substr function, and I'm starting to think I am mis-using it.

PHP Code:

            $code = '
  Events <br />
    Time - Elapsed game time is 300.00 seconds <br />
  Conditions <br />
  Actions <br />';
        $nextline = strpos($code,'<br />');
         while ( $nextline ){
            $line = substr($code,0,$nextline);
                    echo '1LINE ' . $line . '<br />'; // TESTING
            $code = substr($code,$nextline);
                    echo '1CODE ' . $code . '<br />'; // TESTING
            $nextline = strpos($code,'<br />');
                    echo 'NEXTLINE ' . $nextline . '<br />'; // TESTING
        } 


It works the first time around, but only the first time. On the second the nextline is set to 0 and the loop ends. My only guess is that substr removes "<br />"'s from a string, if thats the case, how can I prevent that?