used to use something similar that was pretty much spot on, wish i would have saved the code for you.

I was tired of having to copy and paste all the tech or power/armor/shield numbers from fake attacks into calculators and had basically stopped using calculators for anything except huge attacks. This addon makes those fake attacks show the results right on the page, making it easy to see what will happen (far more accurately, quickly, and effortlessly than my rough estimates I was doing in my head).

In short, I love it!

My only request would be to show the total value of losses from each side, and maybe debris, but it's still really useful as-is. It just works!