Adds a tracking pixel with sale info in the wp_footer on MemberPress Thank You page

tracking_pixel_memberpress_footer.php

<?php
//PASTE THIS CODE IN A PLUGIN LIKE My Custom Functions (RECOMMENDED) OR IN YOUR THEME'S functions.php FILE
function echo_mepr_tracking_script() {
  if(isset($_GET['membership']) && isset($_GET['trans_num'])) {
    $txn = MeprTransaction::get_one_by_trans_num($_GET['trans_num']);
    if(isset($txn->id) && $txn->id > 0) {
      //Echo the script to the HTML footer
      ?>
        <img src="https://www.partner-ads.com/dk/leadtrack.php?programid=&type=salg&ordrenummer=<?php echo urlencode($txn->trans_num); ?>&varenummer=x&antal=1&omprsalg=<?php echo urlencode($txn->amount); ?>" width="1" height="1" style="display:none;" />
      <?php
    }
  }
}
add_action('wp_footer', 'echo_mepr_tracking_script');