We are using Laserfiche Forms Professional Version 10.4.1.172 and have a form that has three separate date fields: production date (ProdDate), completion date (CompDate) and final date (FinalDate).  The fields are hidden/shown depending on the information provided by the user and only one or two of the fields will have a date entered for each submission.  The dates are written to our database so they have to be kept separate.

We need to be able to use the date entered in the appropriate field to determine if the form submission is late. We created a field called LateFeeDate to compare against the current date.  The circumstances that determine which of the three dates is appropriate to use as the LateFeeDate are rather complex so we came up with what we thought would be a simple formula:  =IF(FinalDate>ProdDate,FinalDate,IF(CompDate>ProdDate,CompDate,ProdDate)).  

However, when we preview the form and all three date fields are blank it shows 12/30/99 in LateFeeDate.  Then, when we add dates to fields, it stays 12/30/99 until all three fields are filled out.  Once all three fields are filled out, it shows the correct date, but all three fields will never be filled out by a user.

We assume the problem is comparing a date to an empty value.  How do we change our formula to deal with this?