How do I validate this ?

Question

I use the following code to dynamically generate input fields based on the quantity :
<cfloop from="1" to="#quantity#" index="i">
<table border="0">
<tr>
<td width="33" align="right" class="TitleText"><b>#i#:</b> </td>
<td width="148" align="right" clsas="TitleText">
<cfinput type="text" name="serialNumber" size="40">
<input type="hidden" name="PartNumberID" value="#PartNumberID#"><br></td>
</tr>
</table>
</cfloop>
The problem I am having is that people purposely blowup the serialNumber field by exceeding the limit size 40. I can use maxlenght to prevent this, but I want to display an error message. How can I do this ?

Answer 1

If I give it a unique name, like suggested :
<cfoutput>
<cfloop from="1" to="#quantity#" index="i">
<cfinput type="text" name="serialNumber_#i#" size="40">
</cfloop>
</cfoutput>
How do I validate on the client side (javascript ?) to produce an error message ?
Better yet, how do I insert into a table ? I currently use this code, but the unique rename will change everything :
<cfloop from="1" to="#listlen(form.serialNumber)#" index="i">
<cfset col2 = listgetat(form.gfmPartNumberID, i)>
<cfset col3 = listgetat(form.serialNumber, i)>
    <cfquery name="qryInsertSerial" datasource="test">
    insert into gfmSerialNumbers
    (serialNumberID,
     gfmPartNumberID,
     serialNumber,
     status,
     lineItem,
     closedFlag)
     values
     ('#nextSerialNumberID#',
      '#col2#',
      <cfif col3 is "">
      'None',
      <cfelse>
      '#ucase(col3)#',
      </cfif>
      '1',
      '#i#',
    </cfquery>