一起Polyfill系列：让Date识别ISO 8601日期时间格式

/**
  * 第一种入参模式：无入参，实例化当前日期时间的Date对象
  */
var date1 = new Date();
 
/**
  * 第二种入参模式：短日期格式字符串入参，实例化当前时区日期时间的Date对象
  */
var date2 = new Date(‘2014/12/3‘);
 
/**
  * 第三种入参模式：长日期格式字符串入参，实例化当前时区日期时间的Date对象
  */
var date3 = new Date(‘Aug 3, 2014‘);

/**
  * 第四种入参模式：GMT日期格式字符串入参，实例化指定时区日期时间的Date对象
  */
var date4 = new Date(‘Tue May 25 2014 00:00:00 GMT +0800‘);

/**
  * 第五种入参模式：GMT日期格式字符串入参，实例化0时区日期时间的Date对象
  */
var date5 = new Date(‘Tue May 25 2014 00:00:00 GMT‘);

/**
  * 第六种入参模式：入参依次为年、月、日、时、分、秒和毫秒的数值（其中仅年和月为必填项，日默认值为1，其他默认值为0），实例化当前时区日期时间的Date对象
  */
var date6 = new Date(2014,12,2,1,1,1,1);

// 无论入参是什么，总返回当前时区的GMT日期时间格式的字符串
var dateStr = Date();

    if (!Date.prototype.toISOString){
        var isLeapYear = function(year){
            return (year % 400 === 0) || (year % 4 === 0 && year % 100 !== 0);
        };
        var operHoursAndMinutes = {}; 
        operHoursAndMinutes[‘+‘] = function(minusHours, minusMinutes, year, month, date, hours, minutes, seconds, milliseconds){
            var ret = {};
            minutes -= minusMinutes;
            hours -= minusHours;
            if (minutes < 0){
                hours -= 1;
                minutes += 60;
            }
            if (hours < 0 ){
                --date;
                hours += 24;
                if (date < 0){
                    --month;
                    if (month < 0){
                        --year;
                        month = 11;
                    }
                    if (month % 2 === 0){
                        date += 31;    
                    }
                    else if (month === 1)
                    {
                        date += isLeapYear(year) ? 29 : 28;
                    }
                    else{
                        date += 30;
                    }

                    if (month < 0){
                        --year;
                        month += 12;
                    }
                }
            }

            ret.year = year;
            ret.month = month;
            ret.date = date;
            ret.hours = hours;
            ret.minutes = minutes;
            ret.seconds = seconds;
            ret.milliseconds = milliseconds;

            return ret;
        };
        operHoursAndMinutes[‘-‘] = function(addHours, addMinutes, year, month, date, hours, minutes, seconds, milliseconds){
            var ret = {};

            minutes += addMinutes;
            hours += addHours;
            if (minutes >= 60){
                hours += 1;
                minutes -= 60;
            }
            if (hours >=24){
                ++date;
                hours -= 24;
                var dateOfCurrMonth = month % 2 === 0 ? 31 : (month === 1 ? (isLeapYear(year) ? 29 : 28) : 30);
                if (date >= dateOfCurrMonth){
                    ++month;
                    date -= dateOfCurrMonth;

                    if (month >= 12){
                        ++year;
                        month -= 12;
                    }
                }
            }

            ret.year = year;
            ret.month = month;
            ret.date = date;
            ret.hours = hours;
            ret.minutes = minutes;
            ret.seconds = seconds;
            ret.milliseconds = milliseconds;

            return ret;
        };
        var regExp = new RegExp(‘^(\\d{4,4})‘
                + ‘-((?:0[123456789]|1[012]))‘
                + ‘-((?:0[123456789]|[12]\\d|3[01]))‘
                + ‘T‘
                + ‘((?:[01]\\d|2[0123]))‘
                + ‘:([012345]\\d)‘
                + ‘:([012345]\\d)‘
                + ‘(?:.(\\d{3}))?‘
                + ‘(Z|[+-](?:[01]\\d|2[0123]):?[012345]\\d)$‘);
        var parseISOString2UTC = function(ISOString){
            var ret = {};
            var year = Number(RegExp.$1)
                , month = Number(RegExp.$2) - 1
                , date = Number(RegExp.$3)
                , hours = Number(RegExp.$4)
                , minutes = Number(RegExp.$5)
                , seconds = Number(RegExp.$6)
                , offset = RegExp.$8
                , milliseconds;
            milliseconds = (milliseconds = Number(RegExp.$7), !isNaN(milliseconds) && milliseconds || 0);

            if (offset === ‘Z‘){     
                ret.year = year;
                ret.month = month;
                ret.date = date;
                ret.hours = hours;
                ret.minutes = minutes;
                ret.seconds = seconds;
                ret.milliseconds = milliseconds;
            } 
            else if (typeof offset !== ‘undefined‘){     
                var symbol = offset.charAt(0);
                var offsetHours = Number(offset.substring(1,3));     
                var offsetMinutes = Number(offset.substring(offset.length > 5 ? 4 : 3));

                ret = operHoursAndMinutes[symbol](offsetHours, offsetMinutes, year, month, date, hours, minutes, seconds, milliseconds);
            }

            return ret;
        };
        
        var _nativeDate = Date;
        Date = function(Y,M,D,H,m,s,ms){
            var ret, len = arguments.length;
            if (!(this instanceof Date)){
                ret = _nativeDate.apply(null, arguments);
            }
            else if (len === 1 && typeof arguments[0] === ‘string‘ && regExp.test(arguments[0])){
                var tmpRet;
                try{
                    tmpRet = parseISOString2UTC();
                }
                catch(e){
                    console && console.log(‘Invalid Date‘);
                    return void 0;
                }

                ret = new _nativeDate(_nativeDate.UTC(tmpRet.year, tmpRet.month, tmpRet.date, tmpRet.hours, tmpRet.minutes, tmpRet.seconds, tmpRet.milliseconds));
            }
            else if (typeof arguments[0] === ‘string‘){
                ret = new _nativeDate(arguments[0]);
            }
            else{
                ret = len >= 7 ? new _nativeDate(Y, M, D, H, m, s, ms)
                    : len >= 6 ? new _nativeDate(Y, M, D, H, m, s)
                    : len >= 5 ? new _nativeDate(Y, M, D, H, m)
                    : len >= 4 ? new _nativeDate(Y, M, D, H)
                    : len >= 3 ? new _nativeDate(Y, M, D)
                    : len >= 2 ? new _nativeDate(Y, M)
                    : len >= 1 ? new _nativeDate(Y)
                    : new _nativeDate();
            }

            return ret;
        };
        Date.prototype = _nativeDate.prototype;
        Date.prototype.constructor = Date;

        var _pad = function(num){
            if (num < 10){
                return ‘0‘ + num;
            }
            return num;
        };
        var _padMillisecond = function(num){
            if (num < 10){
                return ‘00‘ + num;
            }
            else if (num < 100){
                return ‘0‘ + num;
            }
            return num;
        };
        Date.prototype.toISOString = function(){
                return [this.getUTCFullYear(), ‘-‘, _pad(this.getUTCMonth() + 1), ‘-‘, _pad(this.getUTCDate()), ‘T‘
                    , _pad(this.getUTCHours()), ‘:‘, _pad(this.getUTCMinutes()), ‘:‘, _pad(this.getUTCSeconds()), ‘.‘, _padMillisecond(this.getUTCMilliseconds()), ‘Z‘].join(‘‘);    
            };

        // 复制可枚举的类成员
        for (var clsProp in _nativeDate){
            if (_nativeDate.hasOwnProperty(clsProp)){
                Date[clsProp] = _nativeDate[clsProp];
            }
        }
        // 复制不可枚举的类成员
        var innumerableMems = [‘UTC‘];
        for (var i = 0, clsProp; clsProp = innumerableMems[i++];){
            Date[clsProp] = _nativeDate[clsProp];
        }

        Date.parse = function(str){
            if ([‘string‘, ‘number‘].indexOf(typeof str) === -1) return NaN;
            
            var isMatch = regExp.test(str), milliseconds = 0;
            if (!isMatch) return _nativeDate.parse(str);

            var tmpRet = parseISOString2UTC();

            return _nativeDate.UTC(tmpRet.year, tmpRet.month, tmpRet.date, tmpRet.hours, tmpRet.minutes, tmpRet.seconds, tmpRet.milliseconds);
        };
        Date.now = Date.now 
            || function(){
                return +new this();
            };
    }