如何使用javascript在数据库中保存下拉选择的值？

控制器

public ActionResult ItemInsert()
        {
            ViewBag.Category = new SelectList(db.CategoryMasters.ToList(), "CategoryId", "CategoryName");
            ItemViewModel item = new ItemViewModel();
            return PartialView(item);
        }

查看

<div class="form-group">
            @Html.LabelFor(model => model.CategoryId, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                    @Html.DropDownList("Category", ViewBag.Category as SelectList, new { @id = "catagory" })
                    @Html.ValidationMessageFor(model => model.CategoryId, "", new { @class = "text-danger" })
            </div>
        </div>

<div class="form-group">
            @Html.LabelFor(model => model.CategoryId, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
               <div hidden>@Html.EditorFor(model => model.CategoryId, new { htmlAttributes = new { @class = "form-control", id = "categoryid" } })</div>
                    @Html.DropDownList("any value", ViewBag.category as SelectList,"--SELECT--", new { @id = "category" })
                    @Html.ValidationMessageFor(model => model.CategoryId, "", new { @class = "text-danger" })
            </div>
        </div>

@LabelFor（model=>model.CategoryId，htmlAttributes:new{@class=“controllabel col-md-2”}）
@Html.DropDownList（“Category”，ViewBag.Category作为SelectList，new{@id=“catagory”}）
@Html.ValidationMessageFor（model=>model.CategoryId，“，new{@class=“text danger”}）

如何使用javascript保存下拉列表值？

查看

<div class="form-group">
            @Html.LabelFor(model => model.CategoryId, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                    @Html.DropDownList("Category", ViewBag.Category as SelectList, new { @id = "catagory" })
                    @Html.ValidationMessageFor(model => model.CategoryId, "", new { @class = "text-danger" })
            </div>
        </div>

<div class="form-group">
            @Html.LabelFor(model => model.CategoryId, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
               <div hidden>@Html.EditorFor(model => model.CategoryId, new { htmlAttributes = new { @class = "form-control", id = "categoryid" } })</div>
                    @Html.DropDownList("any value", ViewBag.category as SelectList,"--SELECT--", new { @id = "category" })
                    @Html.ValidationMessageFor(model => model.CategoryId, "", new { @class = "text-danger" })
            </div>
        </div>

@LabelFor（model=>model.CategoryId，htmlAttributes:new{@class=“controllabel col-md-2”}）
@EditorFor（model=>model.CategoryId，new{htmlAttributes=new{@class=“form control”，id=“CategoryId”}）
@DropDownList（“任意值”，ViewBag.category作为SelectList，”--SELECT--”，new{@id=“category”}）
@Html.ValidationMessageFor（model=>model.CategoryId，“，new{@class=“text danger”}）

JS

<script type="text/javascript">
    $(document).ready(function () {
        $("#category").change(function () {
            var value = $(this).val();
            alert(+value)
            $("#categoryid").val(value);
        });
    });
</script>

$（文档）.ready（函数（）{
$（“#类别”）。更改（功能（）{
var值=$（this.val（）；
警报（+值）
$（“#categoryid”）.val（价值）；
});
});