Problem to change two dropdownlist based on another jQuery

Hello Sir,

I have two dropdownlist select2 based on another. But second drownlist do not working properly in MVC4.

@Html.DropDownList("company11", ViewData["companyy"] as List<SelectListItem>,"Select",new { @class = "validate[required]" })
@Html.DropDownList("brand11", ViewData["brandss"] as List<SelectListItem>,"Select",new { @class = "validate[required]" })

This jquery code:

$("#company11").change(function () {
checkUserIdentity();
var id = $(this).val();
binddropdownn_branch(id);

});

function binddropdownn_branch(id) {

$.ajax({
type: "POST",
url: '/Product/GetbarnchList?id=' + id,
data: {},
contentType: "application/json; charset=utf-8",
dataType: "json",
async: false,
success: function (result) {

$("#brand11").find('option').remove();

$.each(result, function () {

var option = $("<option/>");
option.attr("value", this.Value).text(this.Text);
$('#brand11').append(option);

});


}
});

}