stupid.js

<script type="text/javascript">
  $(document).ready(function() {
    var n = $("tbody>tr").length;
    console.log(n);
    $("#cts").text(n);
    
    $(".filter").change(function () {
      var r = $('tbody>tr:visible').length;
      console.log(r);
    })
    .change();
});
</script>