教程·Javascript 中文手册
Lets you work with dates and times.
| Core object | |
| 实现版本 | Navigator 2.0, LiveWire 1.0 Navigator 3.0: 添加了 prototype 属性 |
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)
| 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. |
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.
| Allows the addition of properties to a Date object. |
| Returns the number of milliseconds in a Date object since January 1, 1970, 00:00:00, Universal Coordinated Time (GMT). |
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)
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, seeFunction.prototype.
| 属性源 | Navigator 3.0, LiveWire 1.0 |
Returns the day of the month for the specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getDate()
无
The value returned by getDate is an integer between 1 and 31.
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()
Returns the day of the week for the specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getDay()
无
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.
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()
Returns the hour for the specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getHours()
无
The value returned by getHours is an integer between 0 and 23.
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()
Returns the minutes in the specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getMinutes()
无
The value returned by getMinutes is an integer between 0 and 59.
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()
Returns the month in the specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getMonth()
无
The value returned by getMonth is an integer between 0 and 11. 0 corresponds to January, 1 to February, and so on.
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()
Returns the seconds in the current time.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getSeconds()
无
The value returned by getSeconds is an integer between 0 and 59.
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()
Returns the numeric value corresponding to the time for the specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getTime()
无
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.
The following example assigns the date value of theBigDay to sameAsBigDay:
theBigDay = new Date("July 1, 1999")
sameAsBigDay = new Date()
sameAsBigDay.setTime(theBigDay.getTime())
Returns the time-zone offset in minutes for the current locale.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getTimezoneOffset()
无
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.
x = new Date()
currentTimeZoneOffsetInHours = x.getTimezoneOffset()/60
Returns the year in the specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
getYear()
无
The getYear method returns either a 2-digit or 4-digit year:
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()
Returns the number of milliseconds in a date string since January 1, 1970, 00:00:00, local time.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
Date.parse(dateString)
:
| dateString | A string representing a date. |
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 thesetTimemethod 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.
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"))
Sets the day of the month for a specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
setDate(dayValue)
| dayValue | An integer from 1 to 31, representing the day of the month. |
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)
Sets the hours for a specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
setHours(hoursValue)
| hoursValue | An integer between 0 and 23, representing the hour. |
theBigDay.setHours(7)
Sets the minutes for a specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
setMinutes(minutesValue)
| minutesValue | An integer between 0 and 59, representing the minutes. |
theBigDay.setMinutes(45)
Sets the month for a specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
setMonth(monthValue)
| monthValue | An integer between 0 and 11 (representing the months January through December). |
theBigDay.setMonth(6)
Sets the seconds for a specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
setSeconds(secondsValue)
| secondsValue | An integer between 0 and 59. |
theBigDay.setSeconds(30)
Sets the value of a Date object.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
setTime(timevalue)
| timevalue | An integer representing the number of milliseconds since 1 January 1970 00:00:00. |
Use the setTime method to help assign a date and time to another Date object.
theBigDay = new Date("July 1, 1999")
sameAsBigDay = new Date()
sameAsBigDay.setTime(theBigDay.getTime())
Sets the year for a specified date.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
setYear(yearValue)
| yearValue | An integer. |
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.
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)
Converts a date to a string, using the Internet GMT conventions.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
toGMTString()
无
The exact format of the value returned by toGMTString varies according to the platform.
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
Converts a date to a string, using the current locale's conventions.
| 方法源 | Navigator 2.0, LiveWire 1.0 |
toLocaleString()
无
If you pass a date using toLocaleString, be aware that different platforms assemble the string in different ways. Using methods such asgetSecondsgives more por表 results.
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
Returns the number of milliseconds in a Date object since January 1, 1970, 00:00:00, Universal Coordinated Time (GMT).
| 方法源 | Navigator 2.0, LiveWire 1.0 |
Date.UTC(year, month, day, hrs, min, sec)
| year | A year after 1900. |
| month | A month between 0 and 11. |
| date | A day of the month between 1 and 31. |
| hrs | (Optional) A number of hours between 0 and 23. |
| min | (Optional) A number of minutes between 0 and 59. |
| sec | (Optional) A number of seconds between 0 and 59. |
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.
The following statement creates a Date object using GMT instead of local time:
gmtDate = new Date(Date.UTC(96, 11, 1, 0, 0, 0))