iPhone cancel button

I saw in the Facebook application for iPhone,on the login page that there is a cancel butto开发者_运维知识库n which can stop the login operation done by the user. How can we build that type of cancel button?

thankz in advance

Whit ASIHTTPRequest, simply [request cancel] as the button action.

From what i know is that facebook provides a login web form for all aplications you can't change it and it does have a cancel button build in. If you want to provide your own implementation of the log in interface you need to register your app whit them,and it takes a while.