Reverse webpage's text on a proxy server

Question

I'm planning April Fool's joke (it's too soon, but I like to be prepared) and I'd like to surprise unsuspecting coworker by reversing his favorite website text and potentially doing some other tricks with the site.

I'd modify his HOSTS file for the website to point to my transparent proxy server, but the latter part is the problem. I'm not particularly skilled with setting up proxies to do tricks, what software should I use for this? I have Linux and Windows machines at my disposal.

Note: For reversing the text, I imagine that reversing text inside each HTML element would do the trick. Maybe regex, maybe DOM parsing.

Answer 1

Look up the Upside-Down-Ternet, which will provide a guide on how to set up Squid as a transparent proxy on linux. You can replace the image modifications with your text modifications to suit your liking.