Strangely, despite what you would think, most browsers still allow popups—even if you’ve disabled them in the normal UI. With Chrome, you can download one of several different popup blocker extensions. With Firefox-based browsers, you can go to about:config, search for dom.popup_allowed_events, and remove all of the entries there. (This does not prevent new windows or tabs from opening when you click on a legitimate link and, so far, I haven’t encountered a site where a desired popup is blocked; but, even if so, you can still allow popups from specific sites.) I’m not sure what’s available for IE as I never use it under normal circumstances.