You will be redirected to <a href="https://www.planet.com">Planet.com</a> in <input type="text" size="3" id="url_time"> seconds
<script>
(function () {
    let redirect_url = "https://www.planet.com";
    let delay = 5; //second
    let input_time = document.querySelector("#url_time");
    let time = input_time.value = delay;
  
    function redirect_page() {
      if (1 < time) {
        time -= 1;
        input_time.value = time;
        setTimeout(redirect_page, 1000);
      } else {
        window.location.href = redirect_url;
      }
    }
    redirect_page();
  })();
</script>