Custom Firefox Facebook Toggle

I am running Firefox 7, OSX and am looking for a custom script. The script would function in the following way: The script would be toggled on/off Once toggled on, it would navigate to: [login to view URL]*USERNAME*?sk=allactivity (where *USERNAME* would be my username) The script would then go through the postings, looking for the ones with similar terms: "posted something via Mob Wars." "posted something via Mob Wars: La Cosa Nostra." "posted something via CityVille." When it identifies the text, I would like the script to then perform the appropriate action to remove the posting from my wall. The script will need to hit the "More Activity" button to search further. When the script cannot find any additional postings, I would like it to turn itself off. If there is additional information required, please feel free to ask!