Companies offering salaries without asking for current compensation

My friend just converted JPMC, he was asked only after clearing all the rounds & while releasing the offer

No one does. But you can always deny answering that. It's upto you and how you present yourself. By the time I reveal my ctc, my expected CTC is talked about and it's met. Companies who cannot meet the ctc, I don't entertain them. I believe in paying fairly

It won't work in India , u always have to share your salary slip , only thing u can try is getting multiple offer

None of the Indian companies AFAIK. Few international ones with good culture does.

Depends a lot on your tech bud