文本框显示/隐藏按钮单击和下拉填充

Question

I am making an functionality where on click of button a textbox should appear, and whatever the user fills the value , it should automatically gets updated in that dropdown. I tried with the below mentioned code, where I am hiding/showing the textbox but unable to fill the dropdown:

<script type="text/javascript">
    $(document).ready(function () {
        $('#ctl00_ContentPlaceHolder1_txtOtherBusiness').hide();
        $("#ctl00_ContentPlaceHolder1_btnbusinessAdd").click(function () {
            $('#ctl00_ContentPlaceHolder1_txtOtherBusiness').show();
        });
        $("#ctl00_ContentPlaceHolder1_btnbusinessAdd").click(function () {
            $('#ctl00_ContentPlaceHolder1_txtOtherBusiness').hide();
        });
    })
</script>

Also see the html for dropdown, textbox and button :-

 <td>
     <asp:DropDownList CssClass="txtfld-popup" ID="ddlBusinessUnit" runat="server"></asp:DropDownList>
     <asp:Button ID="btnbusinessAdd" runat="server" Width="63" Text="Add" CausesValidation="false"/>
     <asp:TextBox ID="txtOtherBusiness" runat="server" Visible="true" CssClass="txtfld-popup" CausesValidation="false"></asp:TextBox>
     <asp:RequiredFieldValidator CssClass="error_msg" ID="reqBusinessUnit" ControlToValidate="ddlBusinessUnit" runat="server" ErrorMessage="Please enter business unit" InitialValue="--Select--" SetFocusOnError="true"></asp:RequiredFieldValidator>
 </td>

Answer 1

for adding value and text to drop down

EDIT: edited the visibility condition

$(document).ready(function () {
        $('#txtOtherBusiness').hide();
        $('#btnbusinessAdd').click(function () {
            if ($('#txtOtherBusiness').is(':visible')) {
                var text = $('#txtOtherBusiness').val();
                var dropDown = $('#ddlBusinessUnit');
                var text = $('#txtOtherBusiness').val();
                var itemVal = 1; // some value for option
                var newItem = $('<option/>').val(itemVal).text(text).appendTo(dropDown);
                $('#txtOtherBusiness').hide();
            }
            else {
                $('#txtOtherBusiness').show();
            }
        });
    });

Answer 2

Simply Use .toggle() in jquery

$("#ctl00_ContentPlaceHolder1_btnbusinessAdd").click(function (event) {
            event.preventDefault();
            $('#ctl00_ContentPlaceHolder1_txtOtherBusiness').toggle();
 });