Ok, this isn't GM scripting, it's ad host hunting. If you want to block CNN and Fox News ads put this into your hosts file. Those are zeros BTW.
0.0.0.0 ad.doubleclick.net ads.cnn.com
Now this isn't visually pleasing because it blocks all ads and the page will look outa whack but it works.
Warning: this resolves those hosts to your computer so if your running a web server on your computer it's gona see the traffic. Hmm, you could configure your server to always respond with a blank page for requests from those hosts/domains.