Where Do You Script To Be Run After Successful Payment?

Darn it, typo in my title. Should be "Where Do You Add Script To Be Run After Successful Payment?"

Want to sync some info from the cs-cart database to another one after customer successfully buys one of our products, therefore I need to run a script (javascript or php, haven't decided yet) after a payment by a customer is successful.

Which script or file does this within the cs-cart hierarchy? And would I be able to accomplish this with "My_Changes"?

Thanks for any help I can get.

use hooks on the order landing page

design/themes/responsive/templates/views/checkout/complete.tpl

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