Basically companies ask for your previous salary because they get to know 2 things in 1. The validity of you claiming to work in that company and also to push down your salary. Come on, lets be honest, if you know some poor bloke is earning Rm2.2K would you ever think of paying him RM5K eventhough his job should be paid that much?

Its an unfair world. If you want to fake, you need extreme guts and to think of all the possible ways the company can check on you. Also be prepared to let go of the job if you are found out.

If you don't want to put the salary, I think it is also OK. Some of my friends have done it and gotten bigger salary. However, the risk is that you better be super good and luck certainly plays a big role. If another bloke is a good as you and puts his salary then you are probably a goner too.