How does login control Validate user with a membership database

As seen in here:

http://msdn.microsoft.com/en-us/library/ms178329.aspx#the_login_control

If you use the Login control with ASP.NET membership, youdo not need to write code to perform authentication.

However, if you want to create your own authentication logic, you can handle theLogin control'sAuthenticate event and add custom authentication code.