index.html

<!-- Display the countdown timer in an element -->
<h1 id="demo"></h1>
<img id="giftimer" src="./Pixel-animate_Boca.gif" width="600"></img>
<br>
<form id="formtohide" action="https://formspree.io/pesaher@gmail.com" method="POST" onsubmit="return myFunction()">
  <input type="text" id="fname" size="20" name="fname">
  <br>
  <input type="submit" value="Try answer"> 
</form>

<script>
// Set the date we're counting down to
var countDownDate = new Date().getTime() + 7200000;

// Update the count down every 1 second
var x = setInterval(function() {

  // Get todays date and time
  var now = new Date().getTime();

  // Find the distance between now and the count down date
  var distance = countDownDate - now;

  // Time calculations for days, hours, minutes and seconds
  var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
  var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
  var seconds = Math.floor((distance % (1000 * 60)) / 1000);

  // Display the result in the element with id="demo"
  document.getElementById("demo").innerHTML = hours + "h "
  + minutes + "m " + seconds + "s ";

  // If the count down is finished, write some text 
  if (distance < 0) {
    clearInterval(x);
    document.getElementById("demo").innerHTML = "0h 0m 0s";
    document.getElementById("giftimer").src = "https://static-s.aa-cdn.net/img/amazon/30600000415955/b5755ff34df2f9a50087ff6cc8d6e71e";
    document.getElementById("formtohide").style.display = "none";
  }
}, 1000);

  function myFunction() {
    var fname = document.getElementById("fname").value;
    submitOK = "false";

    if (fname != "Bernanos Georges") {
        //alert("The answer is not correct");
        //submitOK = "false";
    }
    else
    {
      clearInterval(x);
      document.getElementById("giftimer").src = "./Pixel-animate_finl.gif";
    }
    if (submitOK == "false") {
        return false;
    }
}
</script>