Finding out a saved Facebook password on a iPhone 3GS?

A friend of mine wants to log on to Facebook on her computer, but she forgot her password. She has an iPhone 3GS that has her password set to be remembered so she never had to type it in. Is there a way to figure out what her password is on her phone so she can log in on her home computer? If so, where is it stored, or how do you find out? She can't install apps for some reason, so is there a manual way to find out?