邏輯：分辨大小月，當月例假有幾天，任職區間有幾天例假和休假(自己輸入)，每日薪水多少(除以非假日)
extra holiday(自己總共休假天數-含例假)

//觸發按鈕取input和日期表格內的值,value轉型後變成number
function calculateSalary() {
  const totalSalary = parseFloat(document.getElementById("totalSalary").value); //取薪水
  const startDate = new Date(document.getElementById("startDate").value);
  const endDate = new Date(document.getElementById("endDate").value);
  //"2023-10-25T00:00:00.000Z"
  const extraHoliday = parseInt(document.getElementById("extraHoliday").value); //取例假

  //宣告獲取年分
  const iYear = endDate.getFullYear(); //number型別

  //宣告獲取月份
  const iMonth = endDate.getMonth(); //number型別

  //判斷一個月有幾天
  const daysInMonth = 32 - new Date(iYear, iMonth, 32).getDate();

  const dateBetween = endDate.getDate() - startDate.getDate(); //number型別

  const trueSalary =
    (totalSalary / (daysInMonth - 8)) * (dateBetween - extraHoliday); 

  document.getElementById(
    "result"
  ).innerHTML = `Total Salary for the selected range: ${trueSalary.toFixed(2)}`;

 
}