WHAT IS THE PURPOSE OF AN IPN SCRIPT

The Purpose of the IPN Script is to Update Database at Ecommerce
 Website after Payment at Pay Pal  e.g

(i)  Adding an Order after  Payment By Customer at Pay Pal.

(ii) Adding Payment Record To
     
           (A) Affiliate
           (B) Vendor
      (C) Royalty

     ACCOUNT WITH PAY PAL PAYMENT
      (inorder to zero out Account Balance) so as to prevent
      duplication of payments- since only account with a Balance
      will appear in the Browser for Payment.