What is the error in this code

Question

@section Scripts {

<script>

$(".populateState").on("change", function () {

populateState($(this).val());

})

function populateState(val) {

$.getJSON('@Url.Action("GetStateList", "Buyer")' + "?value=" + val, function (result) {

$(".StateDD").html(""); // makes select null before filling process

var data = result.data;

console.log("---------" + data.length);

if (data.length != 0) {

for (var i = 0; i < data.length; i++) {

$(".StateDD").append("<option value=" + data[i].StateID + ">" + data[i].StateName + "</option>")

}

}

else {

$(".StateDD").append("<option value= 0>No State Added</option>")

populateCity(val, "country");

}

})

}