attendance.js

var isWorkingDay = (year, month ,day, holidays) => (
  moment([year, month, day]).isValid() && 
    moment([year, month, day]).day() >= 1 &&
      moment([year, month, day]).day() <= 5 &&
        !holidays.includes(day)
)

var getWorkingDays = (targetYear, targetMonth, startDay, holidays) => {
  let workingDays = []
  for(let i = startDay; i <= 31; i++) {
    if (isWorkingDay(targetYear, targetMonth, i, holidays)) {
      workingDays.push({year: targetYear, month: targetMonth, day: i});
    }
  }
  return workingDays;
}

var inputTime = (targetYear, targetMonth, targetDay) => {
  console.log(targetYear, targetMonth, targetDay);
  document.getElementById(`ttvTimeSt${moment([targetYear, targetMonth, targetDay]).format('YYYY-MM-DD')}`).click();
  document.getElementById('startTime').value = `9:${getRandomInt(0, 60)}`;
  var endTime = `${getRandomInt(19, 21)}:${getRandomInt(00,60)}`;
  if (!isValidEndTime(moment(endTime, 'HH:mm'))) {
    clearRestTime(); 
  }
  document.getElementById('endTime').value = endTime;
  document.getElementById("dlgInpTimeOk").click();
}

var isValidEndTime = (endTime) => {
  // check if endTime overlaps the restTime.
  var startRestTime = moment(document.getElementById('startRest2'), 'HH:mm');
  var endRestTime = moment(document.getElementById('endRest2'), 'HH:mm');
  return endTime < startRestTime || endTime > endRestTime;
}

var clearRestTime = () => {
  document.getElementById('startRest2').value = '';
  document.getElementById('endRest2').value = '';
}

var mainLoop = (workingDays) => {
  workingDays.forEach((workingDay, index) => {
    setTimeout(() => inputTime(workingDay.year, workingDay.month, workingDay.day), index * 5000);
  })
}

var getRandomInt = (min, max) => Math.floor( Math.random() * (max - min)) + min;

// ============= Input here ===============//
var year = 2018;
var month = 2;
var day = 1;
var holidays = [12]; // Input public holiday or your holiday here. If none, leave as an empty array.
// =========================================//

var workingDays = getWorkingDays(year, month - 1, day, holidays); // month is zero-index

mainLoop(workingDays);