Adding 2 Time formulas in Textboxes to get a total time

Question

I have been trying to add 2 time calculations together to get a total time rounded to the minute, but have been unsucessful.
What I have right now in field "TimeIn1 and TimeOut1" is the calculation on click "$=Num2Time(Time())"
I am tryingto make it so that the person using the form can click in the Time In boxes and have the time automatically entered. Then I want to add 4 fields together
to get a total time spent on a project.
The 4 fields are;
TimeIn1
TimeOut1
TimeIn2
TimeOut2
Total Time
I need it to do the equasion like this;
(Timein1+(TimeOut1-TimeIn2)+TimeOut2)/60=TotalTime
Can anyone help me.Is the easiest way to run the formula as a formcalc or Is a Java Script better.
Please help this newbie.

Answer 1

Here is a script that will do the task in Acrobat, you will have to change the field names and formats to match your form:
// start time
// Start time field name
var cStartName = "StartTime";
// Start time format:
var cStartFormat = "HH:MM";
// end time
// end time field name
var cEndName = "EndTime";
// 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 util.printf("%,101.0f" + ":" + "%,102.0f", 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