Difference Between Popup And Regular Page When Processing Data

I have a form and on submit it goes to the submission page, then writes some data, sends an email and says thank you. I then wanted this to be a pop up window so the user doesn't have to leave the main page, and add an auto close function. The problem is with a popup no variables are passed to it.

The regular code to open a new page was:
Code:
<form name="formRFQ" method="post" onSubmit="return formCheck(this);" action="oring_rfq.php">
This worked perfectly everything submitted fine.

Then I decided to make the window controlled by popup
Code:
<form name="formRFQ" method="post" onSubmit="return formCheck(this);" action="wopen('oring_rfq.php', 'popup', 640, 400); return false;">
Now the page isn't getting any variables.

I wrote an If statement to check if there are any variables in case somebody stumbled on the page without actually submitting any data. So I can tell that no variables are getting sent to the popup..