Hackthis.co.uk : Main level 3
Note  :  You need to understand a logic in code.
Beginning with this challenge .
After the welcome page of challenge 3 
I viewed the source code of page by ctrl+u
I viewed the source code of page by ctrl+u
Highlighted line of code is using if : else condition 
i.e if username = heaven and
password = hell
else alert incorrect login.
i.e if username = heaven and
password = hell
else alert incorrect login.
Explanation : 
if username = heaven , password = hell
it will authenticate otherwise not .
if username = heaven , password = hell
it will authenticate otherwise not .
So providing username as heaven and
password as hell
password as hell
Completed successfully