78680 PHP/JavaScript Popunder Combo

Can this be done? I would like to allow people to link directly to banners that I have hosted on my site. I want them to link via a PHP script using standard image link syntax. i.e. img src="[login to view URL]" The PHP script would then do two things. First it would, of course, return the banner image. Second, it would create a time-delayed popunder that would execute n seconds later and display a specific site. I would like both the URL of the popunder, as well as the time delay, to be variable-driven so I can change them if I want to. I don't require an elaborate admin panel, I can simply edit the variables right in the script.