Using: Acrobat X Pro in windows. 

I have three fields:

1) Today's Date:___________ [DateToday] -- Automatically filled-in with today's date using script.

2) Date Last Payment Made:__________ [LastPaymentMade1] -- Filled-in by user in mm/dd/yyyy format.

3) Months Since Last Payment:______________ [MoBehind] -- Need to calculate from field 1 - 2).

For #3, how do I custom calculate how many MONTHS it has been (#3) since the date the last payment was made (#2)?

There's a great discussion here on this topic but I cannot figure out how to modify the script for my purposes: http://forums.adobe.com/message/1907993#1907993

This appears to be the closest thing to what I want:

function Floor(fValue) { 
return Math.floor(fValue); 
} 
 
 
function Date2Num(sDate, sFormat) { 
var fSecond =1000; 
var fMinute = 60 * fSecond; 
var fHour = 60 * fMinute; 
var fDay = 24 * fHour; 
var oDate = util.scand(sFormat, sDate); 
var fDate = oDate.valueOf(); 
var fDate = fDate / fDay; 
var fDate = Floor(fDate); 
return fDate; 
} 
var Start = this.getField("DateToday").value; 
var sFormat = "mm/dd/yyyy"; 
var End = this.getField("LastPaymentMade1").value; 
var sFormat = "mm/dd/yyyy"; 
var eFormat = sFormat; 
event.value = Date2Num(End, eFormat) - Date2Num(Start, sFormat); 
 

Here's another one that looks SIMILAR to what i want:

(function () {
 
    // Get date from field
    var v = getField("DateToday").value;
 
    if (v) {
 
        // Convert string to date
        var d = util.scand('mm/dd/yyyy', v);
 
        // Add number of days in NUMDAYS field
        d.setDate(d.getDate() - +getField("NumDays").value);
 
        // Set value of this field to the new date
        event.value = util.printd("mm/dd/yyyy", d);
 
 
    } else {
 
        // Blank field if no date entered
        event.value = "";
    }
})();