I would like to know how cookie can be a danger in web application.
I did some research, and they mention cookie stealer, but i am not able to
piece everything up into a picture. For an example: what kind of language will
be affected, what are the tools to use for the stealing, etc.

Anyone has a good and simple demo? By the way this is part of an assignment.
Not intend to be used for attack on any kind of existing web site. It will be great if
someone can come out a demo.