使用JavaScript迭代表单以获得选中的多选、下拉和复选框项

我试图使用javascript迭代表单，但在获取以下表单字段的值时遇到问题：复选框、多选选定项、下拉选定项。以下是我的代码：

var fdata = new FormData();
$("form input[type='text']").each(function (x, y) {
    fdata.append($(y).attr("name"), $(y).val());
});
$("form input[type='hidden']").each(function (x, y) {
    fdata.append($(y).attr("name"), $(y).val());
});

for (var pair of fdata.entries()) {
    alert(pair[0] + ', ' + pair[1]);
}

当前，所有复选框返回为FALSE

我希望多重选择的格式与FormCollection对象的格式相同。i、 e.formcollection对多个选定值进行如下格式化：[Users，{L012，L013}]我不希望将其格式化为[Users，{L012}]，[Users，{L013}]

下面是我在获取数据时遇到问题的字段列表（请注意，我没有包括每个表单元素的所有代码）：

@Html.DropDownListFor（modeleItem=>modeleItem.IssueData.internalExternal，新[]
{new SelectListItem{Text=”“，Value=”“}，
@Html.DropDownListFor（modelItem=>modelItem.IssueData.inOperation，新建[]{
@Html.DropDownListFor（modeleItem=>modeleItem.IssueData.delay，新[]{

当前所有复选框返回为FALSE。请提供有关复选框的当前代码。@Lain-上面的代码都是我的代码。

<select id="coe" multiple="multiple" name="Coes">
    <option value="@item.Value" selected>
</select>
<select asp-for="IssueData.AreaId" asp-items="@(new SelectList(Model.FaList, "AreaId", "Area"))">
</select>
<select id="owners" multiple="multiple" name="Owners">
    <option value="@item.Value" selected>
</select>
<select asp-for="IssueData.originating" asp-items="@(new SelectList(Model.pList, "pId", "pName"))">
</select>
<select id="affected" multiple="multiple" name="Affected">
     <option value="@item.Value" selected>
</option>
@Html.DropDownListFor(modelItem => modelItem.IssueData.internalExternal, new[]
    { new SelectListItem { Text = " ", Value = "" },
<select asp-for="IssueData.VendorID" asp-items="@(new SelectList(Model.VendorList, "VendorID", "Vendor"))">
</select>
@Html.DropDownListFor(modelItem => modelItem.IssueData.inOperation, new[] {
@Html.DropDownListFor(modelItem => modelItem.IssueData.delay, new[] {
<select asp-for="IssueData.QuarterID" asp-items="@(new SelectList(Model.QuarterList, "QuarterId", "Quarter"))">
<input id="revisit" asp-for="@Model.IssueData.revisit" class="revisit" type="checkbox" onclick="onSelectChange(this)" />