Date 的构造方法
new Date();
new Date(value);
new Date(dateString);
new Date(year, monthIndex [, day [, hours [, minutes [, seconds [, milliseconds]]]]]);
- 无参数 ： 取当前时间。
- value ： 相对于 “January 1, 1970, 00:00:00 UTC” 的毫秒。
- dateString ： 符合 IETF-compliant RFC 2822 timestamps 或 ISO 8601 Extended Format（es5开始支持），以及非标格式。
- year, monthIndex [, day [, hours [, minutes [, seconds [, milliseconds]]]]] ： 年月日时分秒
ISO 8601 Extended Format 示例
chrome console> console.log(new Date('2019-12-11T08:30:05+08:00'));
Wed Dec 11 2019 08:30:05 GMT+0800 (中国标准时间)
chrome console> console.log(new Date('2019-12-11T08:30:05'));
Wed Dec 11 2019 08:30:05 GMT+0800 (中国标准时间)
chrome console> console.log(new Date('2019-12-11T08:30:05+00:00'));
Wed Dec 11 2019 16:30:05 GMT+0800 (中国标准时间)
chrome console> console.log(new Date('2019-12-11T08:30:05Z'));
Wed Dec 11 2019 16:30:05 GMT+0800 (中国标准时间)
浏览器兼容
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#Browser_compatibility
参考
https://blog.csdn.net/beta_xiyan/article/details/76991635
https://segmentfault.com/a/1190000017579541
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date
IETF-compliant RFC 2822 timestamps
Date and Time Specification
Date and time occur in several header fields. This section specifies
the syntax for a full date and time specification. Though folding
white space is permitted throughout the date-time specification, it
is RECOMMENDED that a single space be used in each place that FWS
appears (whether it is required or optional); some older
implementations may not interpret other occurrences of folding white
space correctly.
date-time = [ day-of-week "," ] date FWS time [CFWS]
day-of-week = ([FWS] day-name) / obs-day-of-week
day-name = "Mon" / "Tue" / "Wed" / "Thu" /
"Fri" / "Sat" / "Sun"
date = day month year
year = 4*DIGIT / obs-year
month = (FWS month-name FWS) / obs-month
month-name = "Jan" / "Feb" / "Mar" / "Apr" /
"May" / "Jun" / "Jul" / "Aug" /
"Sep" / "Oct" / "Nov" / "Dec"
day = ([FWS] 1*2DIGIT) / obs-day
time = time-of-day FWS zone
time-of-day = hour ":" minute [ ":" second ]
hour = 2DIGIT / obs-hour
minute = 2DIGIT / obs-minute
second = 2DIGIT / obs-second
zone = (( "+" / "-" ) 4DIGIT) / obs-zone
The day is the numeric day of the month. The year is any numeric
year 1900 or later.
The time-of-day specifies the number of hours, minutes, and
optionally seconds since midnight of the date indicated.
The date and time-of-day SHOULD express local time.
The zone specifies the offset from Coordinated Universal Time (UTC,
formerly referred to as "Greenwich Mean Time") that the date and
time-of-day represent. The "+" or "-" indicates whether the
time-of-day is ahead of (i.e., east of) or behind (i.e., west of)
Universal Time. The first two digits indicate the number of hours
difference from Universal Time, and the last two digits indicate the
number of minutes difference from Universal Time. (Hence, +hhmm
means +(hh * 60 + mm) minutes, and -hhmm means -(hh * 60 + mm)
minutes). The form "+0000" SHOULD be used to indicate a time zone at
Universal Time. Though "-0000" also indicates Universal Time, it is
used to indicate that the time was generated on a system that may be
in a local time zone other than Universal Time and therefore
indicates that the date-time contains no information about the local
time zone.
A date-time specification MUST be semantically valid. That is, the
day-of-the-week (if included) MUST be the day implied by the date,
the numeric day-of-month MUST be between 1 and the number of days
allowed for the specified month (in the specified year), the
time-of-day MUST be in the range 00:00:00 through 23:59:60 (the
number of seconds allowing for a leap second; see [STD12]), and the
zone MUST be within the range -9959 through +9959.
形如：
Sun 30 Dec 2018 19:42:44 +0800
ISO 8601 Extended Format
ECMAScript defines a string interchange format for date-times based upon a simplification of the ISO 8601 Extended Format. The format is as follows: YYYY-MM-DDTHH:mm:ss.sssZ
Where the fields are as follows:
YYYY is the decimal digits of the year 0000 to 9999 in the Gregorian calendar.
- “-” (hyphen) appears literally twice in the string.
MM is the month of the year from 01 (January) to 12 (December).
DD is the day of the month from 01 to 31.
T “T” appears literally in the string, to indicate the beginning of the time element.
HH is the number of complete hours that have passed since midnight as two decimal digits from 00 to 24.
: “:” (colon) appears literally twice in the string.
mm is the number of complete minutes since the start of the hour as two decimal digits from 00 to 59.
ss is the number of complete seconds since the start of the minute as two decimal digits from 00 to 59.
. “.” (dot) appears literally in the string.
sss is the number of complete milliseconds since the start of the second as three decimal digits.
Z is the time zone offset specified as “Z” (for UTC) or either “+” or “-” followed by a time expression HH:mm
This format includes date-only forms:
- YYYY
- YYYY-MM
- YYYY-MM-DD
It also includes “date-time” forms that consist of one of the above date-only forms immediately followed by
one of the following time forms with an optional time zone offset appended:
- THH:mm
- THH:mm:ss
- THH:mm:ss.sss
All numbers must be base 10. If the MM or DD fields are absent “01” is used as the value. If the HH, mm, or ss fields are absent “00” is used as the value and the value of an absent sss field is “000”. The value of an absent time zone offset is “Z”.
Illegal values (out-of-bounds as well as syntax errors) in a format string means that the format string is not a valid instance of this format.
NOTE 1 : As every day both starts and ends with midnight, the two notations 00:00 and 24:00 are available to distinguish the two midnights that can be associated with one date. This means that the following two notations refer to exactly the same point in time: 1995-02-04T24:00 and 1995-02-05T00:00
NOTE 2 : There exists no international standard that specifies abbreviations for civil time zones like CET, EST, etc. and sometimes the same abbreviation is even used for two very different time zones. For this reason, ISO 8601 and this format specifies numeric representations of date and time.
精简一下：
ISO 8601 Extended Format ： YYYY-MM-DDTHH:mm:ss.sssZ
示例：
1995-12-17T03:24:00+00:00 //标准时间
1995-12-17T03:24:00Z //标准时间
1995-12-17T03:24:00+08:00 //东8区时间
