Simple Referral system

I need a php script which can generate unique referral for every visitor. ITS FOR CPA PURPOSE What will be script like: 1) On opening of page it should directly generate a referal link ( i should be able to set the refferal link expiration time ) 2) It should be able to implement on any website . like: i will be putting this script in a folder referral and the code which track the no. of referal can be implemented in main [login to view URL] file. In this i can use script in any domain by making a folder referral and adding a referral tracking php code in [login to view URL]