So I have this code, and the function is Like a Search Box ,but if you put the exsact VIDEO ID, you will be Directed to the exsact VIDEO URL and you can play it. But.....

<input type="search" id="testSearch" class="Search" name="" value="" 
placeholder="VIDEO ID">
<button id= "search" onclick="search()" >Search</button>

<script>
function search() {
  var searchtxt = document.getElementById('testSearch').value
window.location.href = "https://mysiteurl.com/"+ searchtxt + ".html";
}
</script>

....how can I make the Video display on an Iframe Box in the same page without leaving the site so that if they want to watch another Video, They will just put again the exsact VIDEO ID on the Search Box and it will display again to the Iframe Box.