下面是另一种更少循环的方法:

calculateTotalMonthsDifference = function(firstDate, secondDate) {
        var fm = firstDate.getMonth();
        var fy = firstDate.getFullYear();
        var sm = secondDate.getMonth();
        var sy = secondDate.getFullYear();
        var months = Math.abs(((fy - sy) * 12) + fm - sm);
        var firstBefore = firstDate > secondDate;
        firstDate.setFullYear(sy);
        firstDate.setMonth(sm);
        firstBefore ? firstDate < secondDate ? months-- : "" : secondDate < firstDate ? months-- : "";
        return months;
}

如果你不考虑每月的日期，这是迄今为止最简单的解决方案

function monthDiff(dateTo, dateTo) 回来了 (12 * (dateTo.getFullYear) - dateyear .getFullYear() 的 /和 控制台(新日期(2000年，01年)，新日期(2000年，02年)// 1 控制台，log(monthDiff, new Date(1999, 02)， new Date(2000, 02)) // 12年 控制台.log(monthDiff，新日期(2009年，11年)，新日期(2010年，0)// 1

注意，月份索引是基于0的。这意味着一月= 0，十二月= 11。

下面是另一种更少循环的方法:

calculateTotalMonthsDifference = function(firstDate, secondDate) {
        var fm = firstDate.getMonth();
        var fy = firstDate.getFullYear();
        var sm = secondDate.getMonth();
        var sy = secondDate.getFullYear();
        var months = Math.abs(((fy - sy) * 12) + fm - sm);
        var firstBefore = firstDate > secondDate;
        firstDate.setFullYear(sy);
        firstDate.setMonth(sm);
        firstBefore ? firstDate < secondDate ? months-- : "" : secondDate < firstDate ? months-- : "";
        return months;
}

它还计算天数并以月为单位进行转换。

function monthDiff(d1, d2) {
    var months;
    months = (d2.getFullYear() - d1.getFullYear()) * 12;   //calculates months between two years
    months -= d1.getMonth() + 1; 
    months += d2.getMonth();  //calculates number of complete months between two months
    day1 = 30-d1.getDate();  
    day2 = day1 + d2.getDate();
    months += parseInt(day2/30);  //calculates no of complete months lie between two dates
    return months <= 0 ? 0 : months;
}

monthDiff(
    new Date(2017, 8, 8), // Aug 8th, 2017    (d1)
    new Date(2017, 12, 12)  // Dec 12th, 2017   (d2)
);
//return value will be 4 months 

function monthDiff(date1, date2, countDays) {

  countDays = (typeof countDays !== 'undefined') ?  countDays : false;

  if (!date1 || !date2) {
    return 0;
  }

  let bigDate = date1;
  let smallDate = date2;

  if (date1 < date2) {
    bigDate = date2;
    smallDate = date1;
  }

  let monthsCount = (bigDate.getFullYear() - smallDate.getFullYear()) * 12 + (bigDate.getMonth() - smallDate.getMonth());

  if (countDays && bigDate.getDate() < smallDate.getDate()) {
    --monthsCount;
  }

  return monthsCount;
}

function calcualteMonthYr(){
    var fromDate =new Date($('#txtDurationFrom2').val()); //date picker (text fields)
    var toDate = new Date($('#txtDurationTo2').val());

var months=0;
        months = (toDate.getFullYear() - fromDate.getFullYear()) * 12;
        months -= fromDate.getMonth();
        months += toDate.getMonth();
            if (toDate.getDate() < fromDate.getDate()){
                months--;
            }
    $('#txtTimePeriod2').val(months);
}