Unreal Tournament is not the only famous FPS that has been ported onto browsers. Quake 3 is now running on browsers thanks to QuakeJS. It is using a port of ioquake3 and emscripten. And guess what? CPMA is one of the mode working on it (along with VanillaQ3 and Q3Fortress).

You can either play a practice game against a bot or an online match. Available maps are cpm1a, cpm3a, cpm22, ztn3tourney1 (for CPMA) and q3dm1, q3dm7, q3dm17 and q3tourney2 on VQ3. Gamesmodes available are FFA, 1V1, CA, CTF and FT for CPMA, and FFA + CTF for VQ3.

Try it out!