Trying to get dropdownlist in ASP.NET

<div class="form-group">
		<table>
			<tr colspan="3">
				<td>
					@Html.LabelFor(Model => Model.CustomerName, new { @class = "Control-lable" })
					@Html.DropDownListFor(m => m.CustomerID, ViewBag.ContList as SelectList, "Select Customer", new { @class = "form-control", @id = "Normal1" })

				</td>

				<td>
					@Html.LabelFor(Model => Model.ShipperName, new { @clsss = "Control-label" })
					@Html.DropDownListFor(m => m.ShipperID, new SelectList("  "), "-- Select Customer --", new { @class = "form-control" })
				</td>
			</tr>
		</table>
	</div>
</body>
</html>
@section Scripts{

	<script src="~/Scripts/jquery-ui-1.10.2.min.js"></script>
	<script src="~/Scripts/jquery.validate.min.js"></script>
	<script src="~/Scripts/jquery.validate.unobtrusive.min.js"></script>

	<script>

		$(document).ready(function () {
			$("#CustomerID").change(function () {
				$.getJSON("/Job/Getshipper", { CustomerID: $("#CustomerID").val() }, function (data) {
					$("#ShipperID").empty();
					$.each(data, function (index, row) {
						$("#ShipperID").append("<option value='" + row.ShipperId + "'>" + row.Shipper_name + "</option>")
					});
				});
			})

			$(function () {
				$("#Normal1").chosen()

			});

		});
	</script>
}

public List<Customer> GetCustomer()
 {
     List<Customer> cust = dc.Customers.ToList();
     return cust;
 }
 public JsonResult Getshipper(int CustomerID)
 {
     dc.Configuration.ProxyCreationEnabled = false;
     List<Shipper> shippers = dc.Shippers.Where(x => x.CustomerID == CustomerID).ToList();
     return Json(shippers, JsonRequestBehavior.AllowGet);
 }

 [HttpGet]
 public ActionResult AddorEdit(int id=0 ,int CustomerID=0)
 {
     ViewBag.ContList = new SelectList(GetCustomer(), "CustomerID", "Customer_Name");


     return View();
 }

 [HttpPost]
 public ActionResult AddorEdit()
 {

     return View();
 }