在JavaScript 中確定年、月、日的日期差異

確定兩個日期之間年、月、日的差異可以由於僅提供一個單位（年、月或日）差異的解決方案不一致或不準確，JavaScript中存在挑戰性

這裡有一個更全面的解決方案，考慮了平年和閏年以及月份之間的確切天數差異：

today = new Date();
past = new Date(2010, 05, 01); // Equivalent to June 1, 2010

function calcDate(date1, date2) {
  // Calculate the difference in milliseconds
  var diff = Math.floor(date1.getTime() - date2.getTime());

  // Convert milliseconds to days
  var day = 1000 * 60 * 60 * 24;
  var days = Math.floor(diff / day);

  // Calculate months and years from days
  var months = Math.floor(days / 31);
  var years = Math.floor(months / 12);

  // Format the message
  var message = date2.toDateString();
  message  = " was ";
  message  = days   " days ";
  message  = months   " months ";
  message  = years   " years ago \n";

  return message;
}

console.log(calcDate(today, past));
// Output: Tue Jun 01 2010 was 1143 days 36 months 3 years ago

此解決方案透過將毫秒數轉換為天數，然後進一步從日期中推導出月份和年份，從而準確計算兩個日期之間的差異總天數。