Self-closing HTML windows

I have a PHP/MySQL database in which I'd like to store sensitive information (like credit card numbers). What I'd like is to have links in certain sections that will open a new, smaller window (or pop-up) ask for a password, display the sensitive information for a specified amount of time (say two minutes) and then close itself if the user doesn't close it before then. I would prefer something PHP-based (or HTML session based) so that we can easily integrate with our code. I am sure something like it could be done with Java/Ajax, but then I wouldn't be able to expand from it myself (without learning Java). ## Deliverables An example workflow is this: I start on a page called [login to view URL] For each client I want a link that says "credit card". (I only need one example link. I can port it into one per client). When you click on "credit card" for client ABC, it will open up a new window, say [login to view URL] and ask for a master password. You enter the master password and then it will display the credit card number. (it can be hard coded for now, I can do the part of pulling from the database). After 2 minutes that window will close itself. I need them to close themselves because we often walk away after opening such sensitive information and I don't want to leave it open for prying eyes. We work primarily in Firefox 2.0.0.14 in tabbed mode so I'm mostly concerned about it auto-closing in Firefox. However, if it worked with IE 6 and 7, that would be great.