AngularJs判断两个日期之前是否超过3个月

function checkTime(){            var begintime = $scope.settlementSheet.validFrom;            var endtime = $scope.settlementSheet.validTo;            if(!endtime){                return true;            }            //判断时间跨度是否大于3个月            var arr1 = begintime.split('-');            var arr2 = endtime.split('-');            arr1[1] = parseInt(arr1[1]);            arr1[2] = parseInt(arr1[2]);            arr2[1] = parseInt(arr2[1]);            arr2[2] = parseInt(arr2[2]);            var flag = true;            if(arr1[0] == arr2[0]){//同年                if(arr2[1]-arr1[1] > 3){ //月间隔超过3个月                    flag = false;                }else if(arr2[1]-arr1[1] == 3){ //月相隔3个月，比较日                    if(arr2[2] > arr1[2]){ //结束日期的日大于开始日期的日                        flag = false;                    }                }            }else{ //不同年                if(arr2[0] - arr1[0] > 1){                    flag = false;                }else if(arr2[0] - arr1[0] == 1){                    if(arr1[1] < 10){ //开始年的月份小于10时，不需要跨年                        flag = false;                    }else if(arr1[1]+3-arr2[1] < 12){ //月相隔大于3个月                        flag = false;                    }else if(arr1[1]+3-arr2[1] == 12){ //月相隔3个月，比较日                        if(arr2[2] > arr1[2]){ //结束日期的日大于开始日期的日                            flag = false;                        }                    }                }            }            if(!flag){                return false;            }            return true;        }