What script would I use for a timesheet using 12:00 am?

Question

I have been able to add a document level script using Acrobat Pro to show midnight as 12:00 am. But my calculations still don't work. As I have it scripted right now a start time of 12:00 am and an end time of 1:00 am equals -11.00 hours not 1.00 hour. What script would I have to add so the calculation is correct?
Here is the script I have right now:
// start time
// Start time field name
var cStartName = "start1mon1";
// Start time format:
var cStartFormat = "HH:MM";
// end time
// end time field name
var cEndName = "end1mon1";
// End time format:
var cEndFormat = "HH:MM";
// some conversion functions
// function to convert time string to minutes
function Time2Num(cTime, cFormat) {
// convert time string to minutes
// convert time string to date object
var oDate = util.scand("mm/dd/yyyy " + cFormat, "01/01/1970 " + cTime);
// convert date object to number of milliseconds
var nTime = oDate.getTime();
// convert milliseconds to minutes and return value
return Math.round(nTime / (1000 * 60));
} // end Time2Num function
function Num2Time(nMinutes) {
// convert time string to Hours and Minute
// hours in nMinues
var nHrs = Math.floor(nMinutes / 60);
// remainder minutes from hours in nMinutes
var nMins = nMinutes / 60;
// return formatted time string
return nHrs, nMins;
} // end Num2Time
// end conversion functions
// perform the calculation using the fields:
// get the values of the fields
var cStartTime = this.getField(cStartName).value;
var cEndTime = this.getField(cEndName).value;
// clear the value
event.value = "";
// test for not null time strings
if(cStartTime != "" && cEndTime != "") {
// compute the time difference in minutes
nDiff = Time2Num(cEndTime, cEndFormat) - Time2Num(cStartTime, cStartFormat);
event.value = Num2Time(nDiff);
} //end not null values
I have no prior knowledge of JavaScript, only what I have found here on the forums and a lot of luck. I would appreciate help on this problem. Thanks!

Answer 1

Thank you Gilad D, that worked making a hidden field and just creating the subtraction for the break with that field!   But for future reference if anyone else comes across this question, this is what I used for the time without subtracting the break.
// Get first field value
var v1 = getField("Finish Time 1").value;
//Split field value
var time1 = v1.split(":");
// Get second field value
var v2 = getField("Start Time 1").value;
//Split field value
var time2 = v2.split(":");
var min1 = time1[0]*60 + time1[1]*1 //
var min2 = time2[0]*60 + time2[1]*1 ;
event.value = ((min1 - min2) / 60) ;
If anyone know how to add a break into this script, have at it! But creating a hidden field with the answer of the above script and then creating another box that takes that number minus a break worked good.