It is possible to display the payment page in a frame or popup but we do not recommend this.
Some browsers will not be able to show the security padlock, which can confuse customers who are shopping on your site. Also, the referrer check performed by the PostFinance server can encounter problems when working with a pop up.
Since the template page is highly customizable, we recommend merchants to display the page in a full browser window and to use the post-sale process to redirect the customer back to the merchant website.