Calculate month year difference b/w. two date

function calculateAge() {
    
    var Bdate = document.getElementById('calculate_age').value;
    var Bday = new Date(Bdate);
    var today=Date.now();
    var dateTo=new Date(today);
   
    var dateFrom=Bday;
   var Q4A = dateTo.getMonth() - dateFrom.getMonth() + 
   (12 * (dateTo.getFullYear() - dateFrom.getFullYear()));
   var year = Math.floor(Q4A/12);
   var month = Q4A%12;
   
    
    $("#age").val(year + ' Year ' + month + ' Month ');
    
}