Does the user enter values in the parent window as well as the pop-up window? And you want to combine all these values? If so then you'll need to submit the form in the parent window at the same time you launch the pop-up, then store that info somewhere your script can get it (perhaps a unique filename which you pass to the pop-up) and then pick it up again with the script that runs when you submit the form in the pop-up.
Confused? I am.
I'm not quite clear about what this means:
I want the values to remain PLUS add the value from the pop up window
... do you mean numerical addition, or more data fields or what? In any event, as I say, you'll need to submit the parent data and save it, then send the pop-up window a filename in a hidden field, so you can find the data again when the pop-up submits.
I promise not to repeat myself again (
sic) if you post some code!
§ George Sherston