changed the welcome.html page a bit.
login and register now works. see extended description for greater description

to see it in action:
node runMail.js
in a web browser go to:
localhost:8888/mail/welcome.html
click on 'go to register'.
enter your details and click login.
you should now be logged in. (a new page will load up saying Hello! ...)
go to:
localhost:8888/mail/welcome.html
enter your username and password.
you should be logged in now. (you should again see the Hello! ....
page).