This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Thinking out loud: You could try placing value in the hidden field with an iterated number in the end. For example: <input type="hidden" name="firstrow<%=i%> value="test"> Then upon clicking the choosing the checkbox, add a snipet of code that retrieves the same value of iterated number of the hidden field with that of the checkbox. Hope that makes sense.