Difference in Months between two dates in JavaScript

Question

How would I work out the difference for two Date() objects in JavaScript, while only return the number of months in the difference?

Any help would be great :)

Answer 1

It also counts the days and convert them in months.

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