Actually, I suppose if the throw with no argument occurs in a catch block, then it can just rethrow whatever was caught (you might omit giving a name to the var

Actually, I suppose if the throw with no argument occurs in a catch block, then it can just rethrow whatever was caught (you might omit giving a name to the variable with the exception if the only thing you will do with it is to rethrow it); in other contexts, it could throw undefined.