Concatenate checkbox value and textbox value into one column

I made a thread about getting all values of checkbox in my database, fortunately it was an easy task. I have 12 list items and the last item is "Others, please specify:", wherein there would be a textbox near it for input. Obviously, it will be use to make additional data that is not included in the list.
Here's it is:


<div class="fieldcourselist"> <asp:CheckBoxList ID="attainment" runat="server" RepeatColumns="2"> <asp:ListItem>B.S. Marine Transportation</asp:ListItem> <asp:ListItem>B.S. Marine Engineering</asp:ListItem> <asp:ListItem>B.S. Associate in Marine Transportation</asp:ListItem> <asp:ListItem>Associate in Marine Engineering</asp:ListItem> <asp:ListItem>B.S. Naval Architecture & Marine Engineerin ...