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Date
Lets you work with dates and times.
创建源
The Date constructor:
new Date()
new Date("month day, year hours:minutes:seconds")
new Date(yr_num, mo_num, day_num)
new Date(yr_num, mo_num, day_num, hr_num, min_num, sec_num)
参数
month, day, year,
hours, minutes,
seconds | String values representing part of a date. | yr_num, mo_num,
day_num, hr_num,
min_num, sec_num | Integer values representing part of a date. As an integer value, the month is represented by 0 to 11 with 0=January and 11=December. |
描述
If you supply no arguments, the constructor creates a Date object for today's date and time. If you supply some arguments, but not others, the missing arguments are set to 0. If you supply any arguments, you must supply at least the year, month, and day. You can omit the hours, minutes, and seconds.
The way JavaScript handles dates is very similar to the way Java handles dates: both languages have many of the same date methods, and both store dates internally as the number of milliseconds since January 1, 1970 00:00:00. Dates prior to 1970 are not allowed.
属性概览
方法概览
示例
The following示例 show several ways to assign dates:
today = new Date()
birthday = new Date("December 17, 1995 03:24:00")
birthday = new Date(95,11,17)
birthday = new Date(95,11,17,3,24,0)
属性
prototype
Represents the prototype for this class. You can use the prototype to add properties or methods to all instances of a class. For information on prototypes, see Function.prototype.
方法
getDate
Returns the day of the month for the specified date.
语法
getDate()
参数
无
描述
The value returned by getDate is an integer between 1 and 31.
示例
The second statement below assigns the value 25 to the variable day, based on the value of the Date object Xmas95.
Xmas95 = new Date("December 25, 1995 23:15:00")
day = Xmas95.getDate()
参看
Date.setDate
getDay
Returns the day of the week for the specified date.
语法
getDay()
参数
无
描述
The value returned by getDay is an integer corresponding to the day of the week: 0 for Sunday, 1 for Monday, 2 for Tuesday, and so on.
示例
The second statement below assigns the value 1 to weekday, based on the value of the Date object Xmas95. December 25, 1995, is a Monday.
Xmas95 = new Date("December 25, 1995 23:15:00")
weekday = Xmas95.getDay()
getHours
Returns the hour for the specified date.
语法
getHours()
参数
无
描述
The value returned by getHours is an integer between 0 and 23.
示例
The second statement below assigns the value 23 to the variable hours, based on the value of the Date object Xmas95.
Xmas95 = new Date("December 25, 1995 23:15:00")
hours = Xmas95.getHours()
参看
Date.setHours
getMinutes
Returns the minutes in the specified date.
语法
getMinutes()
参数
无
描述
The value returned by getMinutes is an integer between 0 and 59.
示例
The second statement below assigns the value 15 to the variable minutes, based on the value of the Date object Xmas95.
Xmas95 = new Date("December 25, 1995 23:15:00")
minutes = Xmas95.getMinutes()
参看
Date.setMinutes
getMonth
Returns the month in the specified date.
语法
getMonth()
参数
无
描述
The value returned by getMonth is an integer between 0 and 11. 0 corresponds to January, 1 to February, and so on.
示例
The second statement below assigns the value 11 to the variable month, based on the value of the Date object Xmas95.
Xmas95 = new Date("December 25, 1995 23:15:00")
month = Xmas95.getMonth()
参看
Date.setMonth
getSeconds
Returns the seconds in the current time.
语法
getSeconds()
参数
无
描述
The value returned by getSeconds is an integer between 0 and 59.
示例
The second statement below assigns the value 30 to the variable secs, based on the value of the Date object Xmas95.
Xmas95 = new Date("December 25, 1995 23:15:30")
secs = Xmas95.getSeconds()
参看
Date.setSeconds
getTime
Returns the numeric value corresponding to the time for the specified date.
语法
getTime()
参数
无
描述
The value returned by the getTime method is the number of milliseconds since 1 January 1970 00:00:00. You can use this method to help assign a date and time to another Date object.
示例
The following example assigns the date value of theBigDay to sameAsBigDay:
theBigDay = new Date("July 1, 1999")
sameAsBigDay = new Date()
sameAsBigDay.setTime(theBigDay.getTime())
参看
Date.setTime
getTimezoneOffset
Returns the time-zone offset in minutes for the current locale.
语法
getTimezoneOffset()
参数
无
描述
The time-zone offset is the difference between local time and Greenwich Mean Time (GMT). Daylight savings time prevents this value from being a constant.
示例
x = new Date()
currentTimeZoneOffsetInHours = x.getTimezoneOffset()/60
getYear
Returns the year in the specified date.
语法
getYear()
参数
无
描述
The getYear method returns either a 2-digit or 4-digit year:
- For years between and including 1900 and 1999, the value returned by getYear is the year minus 1900. For example, if the year is 1976, the value returned is 76.
- For years less than 1900 or greater than 1999, the value returned by getYear is the four-digit year. For example, if the year is 1856, the value returned is 1856. If the year is 2026, the value returned is 2026.
示例
示例 1. The second statement assigns the value 95 to the variable year.
Xmas = new Date("December 25, 1995 23:15:00")
year = Xmas.getYear()
示例 2. The second statement assigns the value 2000 to the variable year.
Xmas = new Date("December 25, 2000 23:15:00")
year = Xmas.getYear()
示例 3. The second statement assigns the value 95 to the variable year, representing the year 1995.
Xmas.setYear(95)
year = Xmas.getYear()
参看
Date.setYear
parse
Returns the number of milliseconds in a date string since January 1, 1970, 00:00:00, local time.
语法
Date.parse(dateString)
参数
:
描述
The parse method takes a date string (such as "Dec 25, 1995") and returns the number of milliseconds since January 1, 1970, 00:00:00 (local time). This function is useful for setting date values based on string values, for example in conjunction with the setTime method and the Date object.
Given a string representing a time, parse returns the time value. It accepts the IETF standard date语法: "Mon, 25 Dec 1995 13:30:00 GMT". It understands the continental US time-zone abbreviations, but for general use, use a time-zone offset, for example, "Mon, 25 Dec 1995 13:30:00 GMT+0430" (4 hours, 30 minutes west of the Greenwich meridian). If you do not specify a time zone, the local time zone is assumed. GMT and UTC are considered equivalent.
Because parse is a static method of Date, you always use it as Date.parse(), rather than as a method of a Date object you created.
示例
If IPOdate is an existing Date object, then you can set it to August 9, 1995 as follows:
IPOdate.setTime(Date.parse("Aug 9, 1995"))
参看
Date.UTC
setDate
Sets the day of the month for a specified date.
语法
setDate(dayValue)
参数
示例
The second statement below changes the day for theBigDay to July 24 from its original value.
theBigDay = new Date("July 27, 1962 23:30:00")
theBigDay.setDate(24)
参看
Date.getDate
setHours
Sets the hours for a specified date.
语法
setHours(hoursValue)
参数
示例
theBigDay.setHours(7)
参看
Date.getHours
setMinutes
Sets the minutes for a specified date.
语法
setMinutes(minutesValue)
参数
示例
theBigDay.setMinutes(45)
参看
Date.getMinutes
setMonth
Sets the month for a specified date.
语法
setMonth(monthValue)
参数
示例
theBigDay.setMonth(6)
参看
Date.getMonth
setSeconds
Sets the seconds for a specified date.
语法
setSeconds(secondsValue)
参数
示例
theBigDay.setSeconds(30)
参看
Date.getSeconds
setTime
Sets the value of a Date object.
语法
setTime(timevalue)
参数
描述
Use the setTime method to help assign a date and time to another Date object.
示例
theBigDay = new Date("July 1, 1999")
sameAsBigDay = new Date()
sameAsBigDay.setTime(theBigDay.getTime())
参看
Date.getTime
setYear
Sets the year for a specified date.
语法
setYear(yearValue)
参数
描述
If yearValue is a number between 0 and 99 (inclusive), then the year for dateObjectName is set to 1900 + yearValue. Otherwise, the year for dateObjectName is set to yearValue.
示例
Note that there are two ways to set years in the 20th century.
示例 1. The year is set to 1996.
theBigDay.setYear(96)
示例 2. The year is set to 1996.
theBigDay.setYear(1996)
示例 3. The year is set to 2000.
theBigDay.setYear(2000)
参看
Date.getYear
toGMTString
Converts a date to a string, using the Internet GMT conventions.
语法
toGMTString()
参数
无
描述
The exact format of the value returned by toGMTString varies according to the platform.
示例
In the following example, today is a Date object:
today.toGMTString()
In this example, the toGMTString method converts the date to GMT (UTC) using the operating system's time-zone offset and returns a string value that is similar to the following form. The exact format depends on the platform.
Mon, 18 Dec 1995 17:28:35 GMT
参看
Date.toLocaleString
toLocaleString
Converts a date to a string, using the current locale's conventions.
语法
toLocaleString()
参数
无
描述
If you pass a date using toLocaleString, be aware that different platforms assemble the string in different ways. Using methods such as getHours, getMinutes, and getSeconds gives more por表 results.
示例
In the following example, today is a Date object:
today = new Date(95,11,18,17,28,35) //months are represented by 0 to 11
today.toLocaleString()
In this example, toLocaleString returns a string value that is similar to the following form. The exact format depends on the platform.
12/18/95 17:28:35
参看
Date.toGMTString
UTC
Returns the number of milliseconds in a Date object since January 1, 1970, 00:00:00, Universal Coordinated Time (GMT).
语法
Date.UTC(year, month, day, hrs, min, sec)
参数
描述
UTC takes comma-delimited date parameters and returns the number of milliseconds since January 1, 1970, 00:00:00, Universal Coordinated Time (GMT).
Because UTC is a static method of Date, you always use it as Date.UTC(), rather than as a method of a Date object you created.
示例
The following statement creates a Date object using GMT instead of local time:
gmtDate = new Date(Date.UTC(96, 11, 1, 0, 0, 0))
参看
Date.parse
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