<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>Page Visibility API</title>
  <script>
    function initiate() {
      document.addEventListener("visibilitychange", showstate);
    }
    function showstate() {
      const element = document.getElementById("application");
      element.innerHTML += "<br>" + document.visibilityState;
    }
    window.addEventListener("DOMContentLoaded", initiate);
  </script>
</head>
<body>
  <section id="application">
    <p>Move to another tab or minimize this window to change the visibility state</p>
  </section>
</body>
</html>