calculate age javascript in adobe acrobat

Question

I am having some difficulties getting a field to populate in an interactive PDF form. I am using a javascript to calculate the current age of client from 2 date fields (DateToday and ClientDOB) already in the form and I need it to populate a "ClientAge" field. The DateToday field automatically populates when the form is opened. I would like for the ClientAge field to populate after the user selects the ClientDOB.

This is what I am trying to have it do. Should be simple I would think.

DateToday - ClientDOB = ClientAge

Here is my code:

var DateToday_ = Date2Num(DateToday.formattedValue, "MM/DD/YYYY")
var ClientDOB_ = Date2Num(ClientDOB.formattedValue, "MM/DD/YYYY")
var diff = DateToday_ - ClientDOB_
ClientAge.value = Floor(diff / 365.25)

I am not sure why the ClientAge field will not populate once the ClientDOB has been selected. Any replies would be helpful. Thanks.

Answer 1

This was taken from somewhere off the 'net. Can' remember where. However I have used this in a number of forms and it works fine. The idea is that the difference between dates is in milliseconds, and a given date is the number of seconds from a fixed date in the past. Once you have the difference in seconds between the dates (in this case DOB to the present) you can calculate how many years that is. Note that my format is in British date format (dd/mm/yy). If you operate in American format (mm/dd/yy) you must make the appropriate changes.

// get current date THIS NON AMERCAN DATE FORMAT
var oNow = new Date();
// get date from 'Demo.DOB' field
var oMyDate = util.scand('dd/mm/yy', this.getField('Demo.DOB').value);
// define second in milliseconds
var nSec = 1000;
// define minute in milliseconds
var nMin = 60 * nSec;
// define hour in milliseconds
var nHr = 60 * nMin;
// define day in milliseconds
var nDay = 24 * nHr;
// compute today as number of days from epoch date
var nNowDays = Number(oNow) / nDay;
// truncate to whole days
nNowDays = Math.floor(nNowDays);
// compute inputted date days from epoch data
var nMyDateDays = Number(oMyDate) / nDay;
// truncate to whole days
nMyDateDays = Math.floor(nMyDateDays);
// compute difference in the number of days
var nDiffDays = nNowDays - nMyDateDays;
// adjust difference for counting starting day as 1
++nDiffDays;
// convert days to years
var nYears = nDiffDays / 365.2525
// truncate to whole years
nYears = Math.floor(nYears);
// set field value number of years (nYears)
event.value = nYears;