Here is a Members Login if username and password is correctly entered then you will be logged in, if incorrect an error message will appear. To test this out:

Login 1

The username is: demo,
The password is: demo.

Login 2

The username is: demo1,
The password is: demo1.

If you go to http://www.aswebs.co.uk/previews/Login without logging on first it will direct you back to this page.