How do I calculate how many days are left in a month?

Question

I'm trying to figure out a way to do this to make a payment apportion using the days left. One of the problems lies in the date being dynamic, since I'm using "whatever today's date is" and it actualizes by day. Any help will be appreciated.

Answer 1

Using some reusable document level scripts for general functions like getting a field object, a date object from a string, and the number of days in a month one could have a script like:
// document level functions;
function GetField(cName) {
// return the field object for named field;
// with error checking;
var oField = this.getField(cName); // get field object;
// test for error getting field;
if(oField == null){
// error accessing field;
app.alert("Error accessing field " + cName);
// return field object;
return oField;
} // end GetField object;
function GetDateObject(cFormat, cDate) {
// get the date object for date cDate with format of cFormat;
var oDate = util.scand(cFormat, cDate);
if(oDate == null) {
app.alert("Error converting date " + cDate + " with format " + cFormat, 0, 0);
return oDate;
} // end GetDateObject function;
function DaysInMonth(cFormat, cDate) {
// return last day of month;
var oDate = GetDateObject(cFormat, cDate);
var StartDate = oDate.getDate(); // get day from date object;
// set date object to 1st of next month;
oDate.setMonth(oDate.getMonth() + 1, 1);
// set date object to pervious date;
oDate.setDate(oDate.getDate() - 1);
// get last day of month;
return oDate.getDate();
} // end DaysInMonth function;
// end document level functions;
// custom calculation script;
// check for needed functions;
if(typeof GetField != "function") app.alert("Missing GetField function!", 0, 0);
if(typeof GetDateObject != "function") app.alert("Missing GetDateObject function!", 0, 0);
if(typeof DaysInMonth != "function") app.alert("Missing DaysInMonthh function", 0, 0);
// some specific data to get value from field;
var cDateName = "MyDateField"; // name of date field;
var cDateFormat = "dd-mmm-yyyy"; // format of date field;
// end specific data;
// get date field object;
var oDateField = GetField(cDateName);
// get the string value for the date;
var cDateValue = oDateField.value;
// convert date value to date object;
var oDate = GetDateObject(cDateFormat, cDateValue);
var nStartDate = oDate.getDate(); // start date for computation;
// the day for the last day of the month
var nLastDayOfMonth = DaysInMonth(cDateFormat, cDateValue);
var DaysToEndOfMonth = nLastDayOfMonth - nStartDate;
event.value = DaysToEndOfMonth;
// end custom calculation script;