引导级联下拉列表knockoutjs

Question

我有两个下拉列表。区域和子区域。当我选择一个区域时，我想填充子区域下拉列表。我有它所有的工作没有击倒，但我不知道如何使用击倒数据绑定，而不是js做处理变化事件。

脚本:? ?

html:

<div class="col-md-10">
    @Html.LabelFor(model => model.AreaID, new { @class = "control-label col-md-2" })
    @Html.DropDownList("AreaID", AreaList, new { @class = "form-control" })
    @Html.ValidationMessageFor(model => model.AreaID)
</div>
<div class="col-md-10">
    @Html.LabelFor(model => model.AreaNodeID, new { @class = "control-label col-md-2" })
    @Html.DropDownList("AreaNodeID", new List<SelectListItem>(), new { @class = "form-control" } )
    @Html.ValidationMessageFor(model => model.AreaNodeID)
</div>

Answer 1

 @Html.DropDownList("AreaID", AreaList, new { @class = "form-control" }, 
                    new { onchange = "FetchStates();" })

function FetchStates() {    
    var countryCode = $("#AreaID").val();
    $.getJSON("/Home/GetStates/" + countryCode, null, function (data) {
        objVM.states(data);
    });