Selectedindexchanged event of dropdownlist is not working with jquery

Selectedindexchanged event of dropdownlist is not working with jquery

USE THIS WORKING FINE

 <div class="form-group col-md-4">
   <label for="txt_RegdId">Letter Type <span class="text-danger">*</span></label>
   <select class="select2 form-control mb-3 custom-select" id="ddl_LetterType" name="ddl_LetterType">
   <option value="-1">Select</option>
   <option value="1">Letter1</option>
   <option value="2">Letter2</option>
   <option value="3">Letter3</option>
   <option value="4">Letter4</option>
   </select>
 </div>
<script>
    $('#ddl_LetterType').change(function () {

        var SelectedValue = $("#ddl_LetterType").val();
        if (SelectedValue > 0) {

            alert(SelectedValue);
        }
    });
</script>

2021-10-03