Temporary Check Box in Form

I have a form showing up to 20 rows of data (records). The user has to check all rows for correct data with a paper document, created by someone from another office. The sequence of the rows are not the same!
What I like to do: have a check box in each row, for rows that are being checked already. I don't want to save this in the DB. With clothing of the form, the information is gone.
How do I do that?
Thanks. Josh