Tab title toggle to recover visitors who went to another tab

tittle-toggle.html

<!-- TITLE TOGGLE - paste this just above the </body> tag -->
<script>
  (function () {

  var t1 = document.title;
  var t2 = 'Come BACK! 💘 DON\'T FORGET ME !!'; // <-- CUSTOMIZE THIS
  var interval;

  window.addEventListener('blur', function () {
    interval = window.setInterval(function () {
      document.title = document.title === t1 ? t2 : t1;
    }, 1000);
  });

  window.addEventListener('focus', function () {
    window.clearTimeout(interval);
    document.title = t1;
  });

  })()
</script>
<!-- END TITLE TOGGLE -->