Dynamically naming text fields

Basically I want to give a unique name to one of my fields as
it is located multiple times in the form. My problem is that once a choice is made from a select list i want to be able to pick up that value and use it to append onto the name of the text field e.g. name="dec_num112". This needs to be done without submitting the form. Once a selection is made in the select list i use a function to compute a value. I then want to set this value to the corresponding text field so that is why i need a unique name for each field. Any ideas?


'Select List

<tr>
<td colspan = 2 class="tblColHead" align="right" valign="center">
<select id="Submission" class="cstyle" name="int_productID" size=1 tabindex="10" onchange="CalcValues(1,document.frmMain.int_productID.value)"
<option value = 0><font color = red>Weight and Price</font></option>
<%

strSelected = ""
Do While Not rsProducts.Eo
with Response
.Write "<option value=" & chr(34) & rsProducts("Productid") & chr(34) & " " & strSelected & ">"
.Write rsProducts("ldesc") & "-" & formatcurrency(formatnumber(rsProducts("Price"),2),2)& "</option>"
End With
rsProducts.MoveNext
Loop
%>
</select>
</td>
</tr>


' Text field
<input class="txtfield" style="BORDER: 0; TEXT-ALIGN: Right; "size=10 name="dec_Num" READONLY>