Calculate number of months between two dates using javascript

var dtFrom= new Date('01/05/2019');
var dtTo= new Date('01/06/2021');

 var fromYear;
    var fromMonth = dtFrom.getMonth() + 1;
    var toYear;
    var toMonth = dtTo.getMonth() + 1;

    if ((fromYear = dtFrom.getFullYear()) < (toYear = dtTo.getFullYear())) {
        toMonth += (toYear - fromYear) * 12;
    }
    var diffMonths = toMonth - fromMonth;
    if (dtFrom.getDate() > dtTo.getDate()) diffMonths--;
   
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For get only the month diff

var dtFrom= new Date('01/05/2019');
var dtTo= new Date('01/06/2021');

 var monthCount = 0;
    while ((dtFrom.getMonth() + '' + dtFrom.getFullYear()) != (dtTo.getMonth() + '' + dtTo.getFullYear())) {
        monthCount++;
        dtFrom.setMonth(dtFrom.getMonth() + 1);
    }
    monthCount  = monthCount + 1;