1. In a program-invocation system that includes a multi-purpose program and a plurality of files, a method of executing the multi-purpose program in either an applet mode or an application mode, such that the same change in behavior in the applet mode and in the application mode is caused by making an update to the multi-purpose program, the method comprising: receiving an invocation directed to a multi-purpose program wherein the invocation is examined by the multi-purpose program; determining whether the invocation is intended to invoke an applet mode of the multi-purpose program or an application mode of the multi-purpose program, wherein the multipurpose program includes an integration of applet mode code and application mode code; executing the multi-purpose program in the applet mode when it is determined that the invocation is intended to invoke an applet mode, wherein when the multi-purpose program is executed in the applet mode, dynamic calls are made to facilitate operation of the multi-purpose program to accomplish a designated function; and executing the multi-purpose program in the application mode when it is determined that the invocation is intended to invoke an application mode, wherein when the multi-purpose program is executed in the application mode, local calls are made to facilitate operation of the multi-purpose program to accomplish the designated function.