function calcLossProductivity(numEmployees,annualSalary,hoursInWeek,numVacationWeeks,hoursLost){

  if(!numEmployees) {

    alert("Please enter a number of employees.");

    return;

  }
  if(!annualSalary) {

    alert("Please enter an annual salary.");

    return;

  }
   if(!hoursInWeek) {

    alert("Please enter total hours.");

    return;

  } 
   if(!numVacationWeeks) {

    alert("Please enter average annual vacation weeks.");

    return;

  }   
   if(!hoursLost) {

    alert("Please enter hours lost.");

    return;

  }     
  
  
  if(isNaN(numEmployees)){

    alert(numEmployees + " is an invalid input. Please make sure you are entering a whole number without commas.");

    return;

  }
  if(isNaN(annualSalary)){

    alert(annualSalary + " is an invalid input. Please make sure you are entering a whole number without commas or dollar signs.");

    return;

  }
   if(isNaN(hoursInWeek)){

    alert(hoursInWeek + " is an invalid input. Please make sure you are entering a whole number.");

    return;

  }
  if(isNaN(numVacationWeeks)){

    alert(numVacationWeeks + " is an invalid input. Please make sure you are entering a whole number.");

    return;

  }
  if(isNaN(hoursLost)){

    alert(hoursLost + " is an invalid input. Please make sure you are entering a whole number.");

    return;

  }
  
  salaryPerHour = numEmployees * ( annualSalary / (52 - numVacationWeeks) / hoursInWeek )
  
  perWeek = hoursLost * salaryPerHour
    
  perMonth = perWeek * 4.33333
  perYear = perWeek * 52

  salaryForm.answerYearly.value="$" + toCurrency(perYear.toString());
  salaryForm.answerMonthly.value="$" + toCurrency(perMonth.toString());
  salaryForm.answerWeekly.value="$" + toCurrency(perWeek.toString());

}



function toCurrency(num) {

  num = Math.round(num*100)/100

  return num.toString();

}