applyCoupon

Method Signature String[] applyCoupon(String couponCode);
Description
Applies a coupon to the cart. The global cart variable is automatically submitted with this call.
Parameters String couponCode – the coupon code to use.
Result String[] –The errors associated with applying the coupon code. These could range from invalid coupon codes to coupon conflicts. If this array contains any values then you should display them to the customer. Even if the errors array contained something the global cart variable is updated automatically.