1. A non-transitory computer-readable storage medium with computer program code embodied thereon, wherein the computer program code is configured to be executed by a processor to: display a first field and a second field together on a user interface of a client system, the first field displayed on the user interface capable of receiving user input on the client system to change a value of the first field, the second field displayed on the user interface having at least an attribute that is dependent upon the value of the first field; detect, on the client system, whether or not the value of the first field has changed; in response to a determination from said detecting that the value of the first field has changed, send the value of the first field for reception at a server system over a network, the server program being configured to process the value of the first field and determine an update to the attribute of the second field; and receive the update to the attribute of the second field from the server system.