Your question prompted a new post on my blog with a sample on how to do complex validations prior to submitting a form. See Complex Validations.

As for reusing script across different forms, that’s possible by using a combination of script objects, subforms and the Library palette: Place a subform on the form and, in the Hierarchy palette, right-click on the subform you just inserted and select Insert Script Object. Then, select the script object and give it a name and use the Script Editor to write script (note that only JavaScript may be used in script objects). Once you’re finished, make the subform invisible using the Object palette’s Subform tab and drag the subform to the Library palette. That’ll create a new object in the Library that you can drag and drop onto any form. Say you named the subform “Subform1″ and the script object “ScriptObject”, you would when access the script by writing a JavaScript (on a button’s Click event, for example) with a statement like “Subform1.ScriptObject.MyFunction();”

The problem with that approach is that if you need to modify the scripts in the script object, you’ll have to go back and fix all the forms that use it because dragging and dropping from the Library onto a form create a copy of that object — not a reference.

Since I’m quite certain you’re looking for a reference rather than a copy, I’ll have to ask you to be a little patient because it’s possible we may address that issue in a future release.