如何从gridview的下拉列表中获取javascript中的选定值

Question

如何在javascript下面检索dropdownlist [ddrateplan]的值，下拉列表位于gridview [DataExtensionList]中。

<asp:GridView ID="DataExtensionList" Width="100%" runat="server" AutoGenerateColumns="False">
<Columns>
    <asp:TemplateField HeaderText="Service No.">
        <ItemTemplate>
            <asp:HiddenField ID="hdid" runat="server" Value='<%#Eval("tran_id") %>' />
            <asp:DropDownList ID="drpphn" runat="server" CssClass="form-control" AutoPostBack="true"
                OnSelectedIndexChanged="drpphn_SelectedIndexChanged" SelectedValue='<%# Eval("phone_no") %>'>
                <asp:ListItem Value="0">Existing no</asp:ListItem>
                <asp:ListItem Value="1">New no</asp:ListItem>
            </asp:DropDownList>
            <asp:TextBox ID="txtservicenumber" runat="server" Text='<%#Eval("service_number") %>'></asp:TextBox>
        </ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Rate Plan">
        <ItemTemplate>
            <asp:DropDownList ID="ddrateplan" runat="server" CssClass="form-control" AutoPostBack="true" onchange="mul();"
                OnSelectedIndexChanged="ddrateplan_SelectedIndexChanged"
                Style="margin: 0 !important; padding: 0 !important;" SelectedValue='<%# Eval("rate_plan") %>'>
                <asp:ListItem Value="0">Select Rate Plan</asp:ListItem>
                <asp:ListItem Value="35">p35</asp:ListItem>
                <asp:ListItem Value="59">p59</asp:ListItem>
                <asp:ListItem Value="89">p89</asp:ListItem>
            </asp:DropDownList>
        </ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Address">
        <ItemTemplate>
            <label>
                <asp:TextBox ID="txt_address" AutoPostBack="true" runat="server" Text='<%# Eval("address")%>'></asp:TextBox>
            </label>
        </ItemTemplate>
    </asp:TemplateField>
</Columns>
</asp:GridView>

这是我试过的javascript的例子，但它不起作用..

 <script type="text/javascript">
     function mul() {

        var gv = document.getElementById("<%=DataExtensionList.ClientID %>");
         var dropvalue = gv.getElementsByTagName('ddrateplan');


         var rowcount = document.getElementById('<%=DataExtensionList.ClientID%>').rows.length;
         var textmonth = document.getElementById('<%=txtcontactperiod.ClientID%>').value;

        var total = 0;
        for (var i = 0; i < rowcount - 1; i++) {
            total += parseInt(dropvalue) * parseInt(textmonth)
        }
        if (textmonth > 0) {
            $("<%=hdvalue.ClientID%>").val(total);
            document.getElementById('<%=txttotalpayble.ClientID%>').value = total;
        }
        else {
            $("<%=hdvalue.ClientID%>").val("");
            document.getElementById('<%=txttotalpayble.ClientID%>').value = '';
        }
    }
</script>

Answer 1

我得到了我的答案只是将dropdown [ddrateplan]的属性添加为clientidmode =“static”并替换javascript的行

     var gv = document.getElementById("<%=DataExtensionList.ClientID %>");
     var dropvalue = gv.getElementsByTagName('ddrateplan');

有了这个

     var dropvalue = $("#ddrateplan").val();