Not looking for anything fancy, but a most simple form of a private/hidden keylogger that will work behind the scenes (undetected) and will only activate when certain sites/urls are opened and the information will be emailed to a specified email address.
Well how big is your budget? A private keylogger made from scratch and FUD isn't easy to make, and it'll cost you.
the problem is Google, you can never hide Javascript from google. any other else is no matter. but the solution is user authorization may be