Why would you do it? If you indicate that the script should only be used by adults, and the person using it is not an adult, your disguising it in the script is not going to stop them using the script, running it, and seeing the web page.
FeaR616, a variable lasts until it's out of scope. If you create a variable within a method and it doesn't have @ at the start, it will cease to exist when the method ends. If it has @ it will cease to exist when the object is deleted. If it has $ at the start, it is global and will cease to exist when you exit the game. If you want a variable saved from one run to another, you must find a way for it to be included in the save data. This is usually by adding it to an appropriate class that's already saved.
Also, I have a Dynamic Features script that will allow you to remove skills that have been added via features during the course of the game.