•You wish to achieve a complex result using multiple script statements. In this case it is convenient to write all the required scripts, as separate functions, in one location (the header) and refer to the functions subsequently in the design document.
•You wish to use a particular script at multiple locations in the design document.
Scripts in modular SPSs
When an SPS module is added to another SPS module, the scripts in the added module are available within the referring SPS, and can be used as event handlers via the Properties sidebar for components in the referring SPS. For more information about using modular SPSs, see the section Modular SPSs.