Scripting help subtracting one day from a user entered date

[JP_NM]

My form is setup for the user to enter a date in the date/time field (1). Area (2) will display the same value as area (1).  In area (3) I want the date in area (1) to subtract one day and display it in (3).  Area (4) will subtract two days from area (1) and display that value. Can someone help with with the scripting?  Thank you.

[whyisthisme]

there are already a few posts that answer this question. Try this one: http://forums.adobe.com/message/5026614#5026614

[JP_NM]

That is a great start, but since I am not a scripting guru (just a beginner), I might need a lot more help.  I have area (1) set as a date/time field, user entered/required.  Areas (2 - 15) are calculated only.