On the checkout page, initialize the IMP object using your Merchant ID.
Client-sideconst IMP = window.IMP; // Can be omitted IMP.init("Merchant ID"); // Example: imp00000000
Client-sideconst IMP = window.IMP; // Can be omitted IMP.init("{Merchant ID}"); // Example: imp00000000a
Be sure to initialize the IMP object only once.
Calling a sub-merchant (Tier) payment window
IMP.agency('Merchant ID', 'ABC'); //ABC = Tier Code