Intercepting popups

I'm looking for some direction on where to start building a small app to squelch popup windows when browsing the Web with IE.

I know there are already a plethora of these programs around so I'm only interested in this as a personal learning project and I don't have much to go on other than curiosity.

The main question I'm trying to answer at this point is where the interception could/should happen and how to handle it. Is it possible to neuter javascript and disallow the window.open method based on some condition without disabling javascript or am I completely off base?

I'd like to stay away from the IP/host blocking methods as I'm not really interested in banners and such right now, just killing the popup windows based on a few rules.

I'd like to implement this as an MFC program as that's what I've been learning lately and would like to apply some of what I've discovered.

Thanks for any pointers!
That1Guy