Rules of Engagement

Role playing fights, for me at least, have always had an element of bad faith to them. While players can plot these battles before acting them out, spontaneous encounters can devolve into a stalemate of two unhittable combatants.

Is it possible to have a system in place that can moderate fights, like a dice or RNG system?

That would be awesome, actually. I know there are a lot of online dice sites (our dm once uses one in a d&d session) but I don't know if that could be incorporated here.