I have an action that returns a file

return File(stream.ToArray(), "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", fileName);

I managed to show the loader on form submit, using javascript

This is my view:

  <form method="post" asp-action="Action" asp-controller="Controller" Area="Area" enctype="multipart/form-data">
     <div class="panel-container show">
         <input type="submit" id="btnUpload" class="col-md-4" />
     </div>
     <div class="spinner-border mx-2" id="loader" role="status">
         <span class="sr-only">Loading...</span>
     </div>     
  </form>

This is the code I added in the JS to make the loading animation start, and it works:

$('#loader').hide();
$(function() {
   $('form').submit(function(){
       $('#loader').show();
   });
});

Now how do I hide it when the action is done doing its deed? Is there any way to do it without using AJAX?