The program I made for the answer is composed entirely of HTML and JavaScript. While I consider myself a rather decent programmer, I'm really not all that professional, so, for lack of better software, I made the program using Notepad (yes, really). The source code can be found here:
https://github.com/KRLW890/krlw890.github.io/blob/master/pkdb-answers/pkmn-w-mirror-stats.html
It uses Papa Parse (
http://papaparse.com/ ) to parse information from veekun (
https://github.com/veekun/pokedex )
If you have any more specific questions about it, feel free to contact me on my wall.