modifying web.config during installation

Question

Hello Friends,

I am working on VS 2010 > Setup and Deployment > Visual Studio Installer > Web Setup Project.

I used to take the database server name from user in the setup wizard. 

Once we get database server name from user we need to modify web.config connection string.

Can anybody please provide sample example or help link to modify web.config in Web Setup Project?

Thanks in advance!

Regards,
Atul Gaikwad