I would like to create auto clicker script for website

I need a website auto clicker script like this-

1.When a visitor visit the site a popup window appear then automatically click "Allow"button .And need to set clicking ratio from (3-14)% .Example if 100 people go to this site then randomly (3-14)% automatically click in the allow button.
2.when a visitor directly go to the site then this script don't work.(If any visitor visit this site without referrer then its don't work).