Rounding / Calc error

[Clarkopolous]

I've having some trouble with either rounding or calculating (or both), values for a timesheet.

I thought my coding was all correct, however it seems to be rounding UP.

Example:

Start time     Break     Finish time     Total hours

    8:30         15 mins         13:15            5.00         Total hours should be 4.50

This is the coding I am using:

var Break = getField("Break1").value;

// start
var start = getField("Start1").value;
var startArr = start.split(":");

// finish
var finish = getField("Finish1").value;
var finishArr = finish.split(":");

//difference
var hourDiff = Math.abs(finishArr[0] - startArr[0]);
var minDiff = Math.floor((Math.abs(finishArr[1] - startArr[1]) / 60)*100);

if (minDiff.toString().length==1)
minDiff = '0' + minDiff;

var output = hourDiff + "." + minDiff;
if((output==Infinity)||isNaN(output)){
event.value="";
} else {
event.value = output-Break;
}

Could someone please assist where I've gone wrong?

FYI - the break gives the value 0.25

[Bernd Alheit]

15 minutes of finish time are lower as the 30 minutes of the start time. In this case you must substract 1 hour.

[Clarkopolous]

Would you be able to assist in how I'd go about that? (Coding if possible)

I am racking my brain and cannot think of the correct way to write it.

Thanks in advance

[Bernd Alheit · Accepted solution]

Replace following lines:

var hourDiff = Math.abs(finishArr[0] - startArr[0]);

var minDiff = Math.floor((Math.abs(finishArr[1] - startArr[1]) / 60)*100);

with this lines:

var hourDiff = Math.abs(finishArr[0] - startArr[0]);

var minDiff = finishArr[1] - startArr[1];

if ((finishArr[1] - startArr[1]) < 0) {

hourDiff = hourDiff - 1;

minDiff = minDiff + 60;

}

minDiff = Math.floor((minDiff / 60)*100);

[Clarkopolous]

Thank you so much for your help.

Works perfectly.