Facebook Auto Like Script for any fanpage --- Not clickjacking

I need a facebook auto like script. The script should work in such a way that every visitor to a website should become a fan of fanpage without having to click on any part of the page. Fanpage address should be configurable in the script The script can not work like an invisible button, etc. If the user is not logged into facebook I do not want a pop up for log in! The script should also work correctly in iframe