Brokerage should be charged only in profits

Is there any Broker in India,where Brokerage is be charged only in profits, so that broker will help clients to earn profits and then earn brokerage, if loss brokerage should be waived off.
Your views

with your method all brokerages will shut down. it should only be charged on losses which discourages losses,not profits thts why zerodha has 60 day challenge if u win the challenge they will refund brokerage upto 6000 generated by you.