How to reset the bootstrap modal when it gets closed and open it fresh again?

I have a list box in the bootstrap modal and a button. When the button is clicked a new button gets rendered inside a div in the modal. When I close the modal and reopen it, the last operation performed on the modal like the button rendered earlier is still present in the modal.

How do reset the modal so that when the modal is opened again, the button is not present and user can again select the option from the list box and click on the button to render a new button and so on.

<!-- Modal -->
<div
  class="modal fade"
  id="myModal"
  tabindex="-1"
  role="dialog"
  aria-labelledby="myModalLabel"
  aria-hidden="true"
>
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal">
          <span aria-hidden="true">&times;</span
          ><span class="sr-only">Close</span>
        </button>
        <h4 class="modal-title" id="myModalLabel">Select Language</h4>
      </div>
      <div class="modal-body">
        <button type="button" class="btn" data-dismiss="modal">Close</button>
        <button type="button" class="btn" id="submit_form">Submit</button>

        <div class="modal-body1">
          <div id="placeholder-div1"></div>
        </div>
      </div>

      <div class="modal-footer">
        <script>
          $("#submit_form").on("click", function () {
            $(".modal-body1").html("<h3>test</h3>");
          });
        </script>

        <script>
          $(function () {
            $(".modal-footer").click(function () {
              $(".modal").modal("hide");
            });
          });
        </script>
      </div>
    </div>
  </div>
</div>

-- Update ---

Why doesn't this work?

<script type="text/javascript">
  $(function () {
    $("#myModal").on("hidden.bs.modal", function (e) {
      console.log("Modal hidden");
      $("#placeholder-div1").html("");
    });
  });
</script>

Just reset any content manually when modal is hidden:

$(".modal").on("hidden.bs.modal", function(){
    $(".modal-body1").html("");
});

There is more events. More about them here

$(document).ready(function() {
  $(".modal").on("hidden.bs.modal", function() {
    $(".modal-body1").html("Where did he go?!?!?!");
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.1/css/bootstrap.min.css" />
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js"></script>

<button type="button" class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal">
  Launch modal
</button>

<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span>
        </button>
        <h4 class="modal-title" id="myModalLabel">Modal title</h4>
      </div>
      <div class="modal-body">
        <div class='modal-body1'>
          <h3>Close and open, I will be gone!</h3>
        </div>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
      </div>
    </div>
  </div>
</div>

Tried it and working well

$('#MyModal').on('hidden.bs.modal', function () {
    $(this).find('form').trigger('reset');
})

reset is dom build-in funtion, you can also use $(this).find('form')[0].reset();

And Bootstrap's modal class exposes a few events for hooking into modal functionality, detail at here.

hide.bs.modal This event is fired immediately when the hide instance method has been called.

hidden.bs.modal This event is fired when the modal has finished being hidden from the user (will wait for CSS transitions to complete).