After completing missions 1-4 with ease I have just spent HOURS on mission 5. Allow me to share my finding:
It does not work with the current version of Firefox!!!
either of the suggested methods!
KILL. ME. NOW.
I only downloaded FF as Hack this Site recomended it - classic.
Should an admin not confirm this, and either update the task or at least post a warning?
If you have been getting more and more confused as you read every single article or page ever posted on the web about js injection, look on the bright side - you now know a lot more about the subject than if the task worked as it should.
For those confused by the interface:
If you get:
"Password reminder successfully sent."
that is intended to demonstrate that an email has been sent - but not to you. i.e. try something else (or the same thing in IE)
You do not actually get emailed (shame, would have been a nice touch

)
If you pass, the response is a page with the password on it.
Big Love x