I would't know enough to write such an application, and certainly wouldn't go downloading anything like that, but I'm assuming you only have one or two particular websites in mind? If you aren't in need of something that works with a wide range of different sites, and the email addresses are on a relatively small number of pages, then it may be possible to do it in a cruder way by downloading the page and importing it into Excel and searching and sorting; this will be much harder if it is something like a bulletin board of course.
PS- your personal message inbox is full and bouncing...