A method for displaying a function interface at a computing device, the method comprising: receiving, at the computing device, information input by a user at an interface of a first service provided by an application installed at the computing device, wherein the computing device stores a keyword library including keywords indicating corresponding different services as intended to be used by the user, wherein the interface is a chat interface and the first service is a chat service; determining, by the computing device, a keyword in the information based on the keyword library; displaying, by the computing device, a function interface of a second service corresponding to the keyword according to the keyword library, wherein the keyword library comprises a preset correspondence between keywords and function interfaces corresponding to the different services; and after determining that the determined keyword is a preset keyword related to a payment service and displaying the function interface of the second service the second service being the payment service, if a numeric character is included in the information: a) extracting the numeric character in the information, b) adding the numeric character to a designated region in the function interface, and c) prompting the user to confirm, at the function interface, whether the added numeric character is a correct payment amount and executing a payment operation at the payment service according to the added numeric character; and if no numeric character is included in the information: receiving a numeric character from a manual interaction of the user with the function interface of the payment service to provide a payment amount, and prompting the user to confirm, at the function interface, whether the received numeric character is a correct payment amount, and executing a payment operation at the payment service according to the received numeric character. receiving, at the computing device, information input by a user at an interface of a first service provided by an application installed at the computing device, wherein the computing device stores a keyword library including keywords indicating corresponding different services as intended to be used by the user, wherein the interface is a chat interface and the first service is a chat service; determining, by the computing device, a keyword in the information based on the keyword library; displaying, by the computing device, a function interface of a second service corresponding to the keyword according to the keyword library, wherein the keyword library comprises a preset correspondence between keywords and function interfaces corresponding to the different services; and after determining that the determined keyword is a preset keyword related to a payment service and displaying the function interface of the second service the second service being the payment service, if a numeric character is included in the information: a) extracting the numeric character in the information, b) adding the numeric character to a designated region in the function interface, and c) prompting the user to confirm, at the function interface, whether the added numeric character is a correct payment amount and executing a payment operation at the payment service according to the added numeric character; and if no numeric character is included in the information: receiving a numeric character from a manual interaction of the user with the function interface of the payment service to provide a payment amount, and prompting the user to confirm, at the function interface, whether the received numeric character is a correct payment amount, and executing a payment operation at the payment service according to the received numeric character. if a numeric character is included in the information: a) extracting the numeric character in the information, b) adding the numeric character to a designated region in the function interface, and c) prompting the user to confirm, at the function interface, whether the added numeric character is a correct payment amount and executing a payment operation at the payment service according to the added numeric character; and a) extracting the numeric character in the information, b) adding the numeric character to a designated region in the function interface, and c) prompting the user to confirm, at the function interface, whether the added numeric character is a correct payment amount and if no numeric character is included in the information: receiving a numeric character from a manual interaction of the user with the function interface of the payment service to provide a payment amount, and prompting the user to confirm, at the function interface, whether the received numeric character is a correct payment amount, and executing a payment operation at the payment service according to the received numeric character. receiving a numeric character from a manual interaction of the user with the function interface of the payment service to provide a payment amount, and prompting the user to confirm, at the function interface, whether the received numeric character is a correct payment amount, and executing a payment operation at the payment service according to the received numeric character.