jsは2つの時間の間に月を違います.

/**
 *           
 */
function getMonths(start, end){
	var result = [];
    var starts = start.split('-');
    var ends = end.split('-');
    var staYear = starts[0]*1;
    var staMon = starts[1]*1 < 10? starts[1]:starts[1];
    var endYear = ends[0]*1;
    var endMon = ends[1]*1 < 10? ends[1]:ends[1];;
    result.push(staYear+'-'+staMon);
    while (staYear <= endYear) {
        if (staYear === endYear) {
            while (staMon < endMon) {
                staMon++;
                if(staMon < 10){
                	result.push(staYear+'-0'+staMon);
                }else{
                	result.push(staYear+'-'+staMon);
                }
            }
            staYear++;
        } else {
            staMon++;
            if (staMon > 12) {
                staMon = 1;
                staYear++;
            }
            if(staMon < 10){
            	result.push(staYear+'-0'+staMon);
            }else{
            	result.push(staYear+'-'+staMon);
            }
        }
    }
    return result;
}

/**
 *         
 * @param date
 * @param num
 */
function getfMonths(date, num){
	var dates = date.split('-');
	var year = dates[0]*1;
	var month = dates[1]*1;
	var i = 1;
	var result = [];
	result.push(dates[0]+'-'+dates[1]);
	while(i < num){
		month++;
		if(month < 10){
			result.push(year+'-0'+month);
		}else{
			if(month < 13){
				result.push(year+'-'+month);
			}else{
				month = 1;
				year++;
				result.push(year+'-0'+month);
			}
		}
		i++;
	}
	return result;
}

/**
 *         
 * @param date
 * @param num
 */
function getlMonths(date, num){
	var dates = date.split('-');
	var year_ = dates[0]*1;
	var month_ = dates[1]*1;
	var i = num;
	var result = [];
	while(i > 0){
		i--;
		var month = month_;
		var year = year_;
		if(i == 0){
			result.push(dates[0]+'-'+dates[1]);
		}else{
			if(month_ < num){
				month += 12;
				year--;
				month -= i;
				if(month < 10){
					result.push(year+'-0'+month);
				}else{
					if(month == 13){
						month = 1;
						result.push(year+'-0'+month);
					}else{
						result.push(year+'-'+month);
					}
				}
			}else{
				month -= i;
				if(month < 10){
					result.push(year+'-0'+month);
				}else{
					result.push(year+'-'+month);
				}
			}
		}
	}
	return result;
}