mvc razor dropdownlist onchange selection

<script>

    function customerChangefunc(item) {

        alert(item);

    }

</script>

<div class="form-group">

    <label class="control-label col-sm-4">Customers</label>

    <div class="col-sm-8">

        @{                                 

            var custLst =new List<SelectListItem>();

            foreach (var item in Model)

            {

                custLst.Add(new SelectListItem() { Text = item.crmCustomerName, Value = item.erpCustomerId });

            }                               

            @Html.DropDownList("erpCustomerId", custLst, "--Choose Customer--", new { id = "adepCustomerId", @class = "form-control", @onchange = "customerChangefunc(this.value)" })   

        }                                                        

    </div>

</div>