Custom modifications in delivery Input form
Hi all,
When creating a new delivery template below fields needs to be filled in delivery properties general tab.

Here I need to test the condition if campaign is valid to date is less than or equal to today, Then the campaign is valid to date should save 30 days prior to current date while save the delivery template.
My question is,
1. how to check the campaign is valid to date is less than or equal to today?
2. If campaign is valid to date is less than or equal to today, how to set campaign is valid to date is prior to current date?
3. In which Input form above changes need to be done?
Thanks in Advance.
Best Regards,
Ram.