Not to be mean, but that sounds like a really bad idea to me. I hate doing stuff in web browsers. I typically even write forum posts outside of the browser window then copy/paste them in because they're so prone to accidents/errors that can cause you to lose all of your data.
Just imagine...
"Awesome, I've almost completed my masterpiece. All I have to do is ... OH @^$#! I HIT THE BACK BUTTON!"
Another thing I'm prone to do is hit ctrl+w, since v and w are next to each other in Dvorak. Then there's the browser instability issues, massive overhead, etc. If your computer can't run bsp... well, you probably can't run paintball2 to begin with, but that aside, there's no way a web equivalent would run. Firefox (or whatever browser you use) would probably be using like 1 gig of memory and run like a dog.