Applescript Editor question

Ok i am trying to make an application that will tell you when someone logs onto your computer by making it a logon item and it will write a date on a text file.

My question is how do i use a password on applescript, so i type in a password and if it is right it will let me through if not i get 2 more attempts before it closes the app?

Sorry, but your explanation makes little sense. Is this for your user account, or for someone else's? If someone logs into your user account, obviously they'd have your password, so what would be the point?

Surely you're not giving the password to your user account out to other people, right?