Timesheet Help - Javascript

I have created a PDF form that I need help with solving a few minor issues. If an employee needs out time is after midnight I need for it to calculate correctly. I would also like for 12:00 AM to appear as 12:00AM and not 00:00.

function CalculateDay( myDay ) {

var myColumn

var myDayError = new Boolean
var myTotalWork = new Boolean
var myDayLeaveError = new Boolean
var myTotalHours = new Boolean

var myInAndOut = new Array(6)
var myInAndOutTime = new Array(6)

var myLeaveColumns = new Array("Vacation", "Sick", "Other")
var myLeaveColumn
var myLeave

myDayError = false
myTotalWork = 0

for (myColumn = 1; myColumn <= 6; myColumn++) {
 
  myInAndOut[myColumn] = this.getField("Day" + myDay + "Column" + myColumn).value

  if (myInAndOut[myColumn].length > 0) {

   myInAndOutTime[myColumn] = new Date()

   myInAndOutTime[myColumn].setSeconds(0)
   myInAndOutTime[myColumn].setMilliseconds(0)

   if (myInAndOut[myColumn].charAt(1) == ":") {
    myInAndOutTime[myColumn].setHours(myInAndOut[myColumn].substring(0,1))
    myInAndOutTime[myColumn].setMinutes(myInAndOut[myColumn].substring(2,4))
   }
   else if (myInAndOut[myColumn].charAt(2) == ":") {
    myInAndOutTime[myColumn].setHours(myInAndOut[myColumn].substring(0,2))
    myInAndOutTime[myColumn].setMinutes(myInAndOut[myColumn].substring(3,5))
   }

   if (myInAndOut[myColumn].substring(myInAndOut[myColumn].length - 2, myInAndOut[myColumn].length).toLowerCase() == "pm" ||
       myInAndOut[myColumn].substring(myInAndOut[myColumn].length - 2, myInAndOut[myColumn].length).toLowerCase() == "am" ||
       myInAndOut[myColumn].substring(myInAndOut[myColumn].length - 1, myInAndOut[myColumn].length).toLowerCase() == "p" ||
       myInAndOut[myColumn].substring(myInAndOut[myColumn].length - 1, myInAndOut[myColumn].length).toLowerCase() == "a") {
       if (myInAndOut[myColumn].substring(0,2) == 12) {
     myInAndOutTime[myColumn].setHours(24)
    }
    if (myInAndOut[myColumn].substring(myInAndOut[myColumn].length - 2, myInAndOut[myColumn].length).toLowerCase() == "pm" ||
     myInAndOut[myColumn].substring(myInAndOut[myColumn].length - 1, myInAndOut[myColumn].length).toLowerCase() == "p") {
     myInAndOutTime[myColumn] = new Date(myInAndOutTime[myColumn].valueOf() + 12 * 60 * 60 * 1000)
    }
   }

   if ( (myColumn == 2 || myColumn == 4 || myColumn == 6) && myInAndOutTime[myColumn].getHours() == 0  && myInAndOutTime[myColumn].getMinutes() == 0 ) {
    myInAndOutTime[myColumn] = new Date(myInAndOutTime[myColumn].valueOf() + 24 * 60 * 60 * 1000)
    console.println (myInAndOutTime[myColumn])
   }

  }
}

for (myColumn = 1; myColumn <= 5; myColumn += 2) {
  if (myInAndOut[myColumn].length > 0 && myInAndOut[myColumn + 1].length > 0) {
   if (myInAndOutTime[myColumn + 1].valueOf() > myInAndOutTime[myColumn].valueOf()) {
    myTotalWork += ((myInAndOutTime[myColumn + 1].valueOf() - myInAndOutTime[myColumn].valueOf()) / 60 / 1000)
   }
   else {
    myDayError = true
   }
  }
}

for (myColumn = 2; myColumn <= 4; myColumn += 2) {
  if (myInAndOut[myColumn].length > 0 && myInAndOut[myColumn + 1].length > 0) {
   if (myInAndOutTime[myColumn].valueOf() > myInAndOutTime[myColumn + 1].valueOf()) {
    myDayError = true
   }
  }
}

if (myDayError == false) {
     myTotalWork = Math.round(myTotalWork / 60 * 4) / 4
     if (myTotalWork > 0) {
   this.getField("Day" + myDay + "TotalWork").value = myTotalWork.toFixed(2)
  }
  else {
   this.getField("Day" + myDay + "TotalWork").value = ""
  }
 
  myDayLeaveError = false

  myTotalHours = myTotalWork

  for (myLeaveColumn = 0; myLeaveColumn < myLeaveColumns.length; myLeaveColumn++) {
   myLeave = this.getField("Day" + myDay + myLeaveColumns[myLeaveColumn]).value

   if (myLeave.toString().length > 0) {
    if (typeof(myLeave) == "number") {
     if (myLeave >= 0) {
      myTotalHours += Math.round(myLeave * 4) / 4
     }
     else {
      myDayLeaveError = true
     }
    }
    else {
     myDayLeaveError = true
    }
   }
  }

  if (myDayLeaveError == false) {
   if (myTotalHours > 0) {
    this.getField("Day" + myDay + "TotalHours").value = myTotalHours.toFixed(2)
   }
   else {
    this.getField("Day" + myDay + "TotalHours").value = ""
   }
  }
  else {
   this.getField("Day" + myDay + "TotalHours").value = "Error!"
  }

}
else {
  this.getField("Day" + myDay + "TotalWork").value = "Error!"
  this.getField("Day" + myDay + "TotalHours").value = "Error!"
}

}

Below is a screenshot of what I have currently. Any help is greatly appreciated.