如何从html检索jQuery值

模式触发器:

<a data-toggle='modal' data-name='$nameCap' data-id='$id' class='open-DeleteDialog' href='#deleteDialog'><i class='fas fa-trash-alt'></i></a>

主要工作:

$(document).on("click", ".open-DeleteDialog", function () {
    var categoryId = $(this).data('id');
    var categoryName = $(this).data('name');
    $("#categoryId").val( categoryId );
    $('#deleteConfirmation').text("Are you sure you want to delete this category: " + categoryName + "?");
});

模态内部:

  <div class="modal-body">
    <div id="deleteConfirmation">
      <!-- Filled with confirmation from jquery -->
    </div>
  </div>
  <div class="modal-footer">
    <button type="button" class="btn btn-secondary" data-dismiss="modal">Cancel</button>
    <button id="saveChanges" type="button" class="btn btn-danger">Delete</button>
    <script>

      $(function() {

        $('#saveChanges').on('click', function() {
          var id = $( "#categoryId").val();
          console.log(id)
        });


      });
    </script>

我试图获取categoryId值,但在记录时,它返回未定义的值。我做错什么了?