On Cancel

Cancel event element.on(event: string, handler: function) The cancel event is triggered when the payment interface is dismissed (e.g. the customer closes it). Note that in some browsers, the payment interface might be dismissed by the customer even after they authorize the payment. This means that you might receive a cancel event after receiving a confirm event. If you're using the cancel event as a hook for canceling the customer's order, make sure you also refund the payment that you just created. The following Checkout Elements support the cancel event: expressCheckoutElement and checkoutForm.