echo '

        <script type="text/javascript">
        $(document).ready(function () {

            $(".open' . $popupCounter . '").on("click", function() {
              $(".popup-overlay' . $popupCounter . ', .popup-content' . $popupCounter . '").addClass("active");
            });

            $(".close' . $popupCounter . ', .popup-overlay' . $popupCounter . '").on("click", function() {
              $(".popup-overlay' . $popupCounter . ', .popup-content' . $popupCounter . '").removeClass("active");
            });
        });
        </script>

        '

Issues