bootstrap modal how x button works code example

Example: modal boostrap

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

<div class="modal fade" id="modalId">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">title</h5>
		<button type="button" class="close" data-dismiss="modal" aria-label="Close">
        	<span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        
      </div>
      <div class="modal-footer">
  		<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="submit" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>