hi ,how to make two dropdowns in my page editable.?ie, if user dnt find what is required for him in ddl, he shud be able to insert his value ?

<div class="row-fluid form-horizontal form-bordered">
                    <div class="control-group">
                        <label class="control-label" for="txtName">From Area:</label>
                        <div class="controls">
                            <asp:DropDownList ID="drpFromArea" runat="server" CssClass="input-block-level" ></asp:DropDownList>
                        </div>
                    </div>
                    <div class="control-group">
                        <label class="control-label" for="txtName">To Area:</label>
                        <div class="controls">
                            <asp:DropDownList ID="drpToArea" runat="server" CssClass="input-block-level" OnSelectedIndexChanged="drpToArea_SelectedIndexChanged"></asp:DropDownList>
                        </div>
                    </div>
                </div>