THOMASSSSS, Check out this link. I think it may help you do your thing. https://rominirani.com/episode-14-writing-a-chrome-extension-powered-by-app-engine-23bc574fc95b Good luck, bros.
https://drive.google.com/open?id=1jKEt_gwbC_qhLl6qwZN0WP-qoXCljleq This is the link to the zip file.
Chrome extension takes keyword and redacts it from (most)webpages.