Date : Object

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本文详细介绍了JavaScript中的Date对象，包括构造函数、属性、本地时间和通用时间的方法等，并提供了丰富的使用示例。

Date : Object

Lets you work with dates and times.

Browser/User Agent Support

IE	Mozilla	Netscape	Opera	Safari
3.0+	1.0+	2.0+	7.0+	1.0+

Constructors

Constructor	IE	Mozilla	Netscape	Opera	Safari
Date Constructor Creates a new instance of a Date object.	3.0+	1.0+	2.0+	7.0+	1.0+
Date Constructor Creates a new instance of a Date object.

Properties

Property	IE	Mozilla	Netscape	Opera	Safari
constructor Specifies the function that creates an object's prototype. Note that the value of this property is a reference to the function itself, not a string containing the function's name.	4.0+	1.0+	3.0+	7.0+	1.0+

prototype Represents the prototype for this class. You can use the prototype to add properties or methods to all instances of a class.	4.0+	1.0+	3.0+	7.0+	1.0+

Methods

Method	IE	Mozilla	Netscape	Opera	Safari
getDate Returns the day of the month for the specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

getDay Returns a number representing the day of the week for the specified date (according to local time).	3.0+	1.0+	2.0+	7.0+	1.0+

getFullYear Returns the year of the specified date according to local time.	4.0+	1.0+	4.06+	7.0+	1.0+

getHours Returns the hour for the specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

getMilliseconds Returns the number of milliseconds in the specified date according to local time.	4.0+	1.0+	4.06+	7.0+	1.0+

getMinutes Returns the minutes in the specified date according to local time.	4.0+	1.0+	2.0+	7.0+	1.0+

getMonth Returns the month (from 0-11) in the specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

getSeconds Returns the seconds in the specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

getTime Returns the numeric value corresponding to the time for the specified date according to universal time.	3.0+	1.0+	2.0+	7.0+	1.0+

getTimezoneOffset Returns the time-zone offset in minutes for the current locale.	3.0+	1.0+	2.0+	7.0+	1.0+

getUTCDate Returns the day (date) of the month in the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getUTCDay Returns the day of the week in the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getUTCFullYear Returns the year in the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getUTCHours Returns the hours in the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getUTCMilliseconds Returns the milliseconds in the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getUTCMinutes Returns the minutes in the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getUTCMonth Returns the month of the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getUTCSeconds Returns the seconds in the specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

getYear Returns the year in the specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

now Returns the number of milliseconds passed since 1970-01-01 00:00:00 UTC.	no	1.0+	no	no	no

parse Parses a string representation of a date, and returns the number of milliseconds since January 1, 1970, 00:00:00, local time.	3.0+	1.0+	2.0+	7.0+	1.0+

setDate Sets the day of the month for a specified date according to local time.	4.0+	1.0+	2.0+	7.0+	1.0+

setFullYear Sets the full year for a specified date according to local time.	4.0+	1.0+	4.06+	7.0+	1.0+

setHours Sets the hours for a specified date according to local time.	4.0+	1.0+	2.0+	7.0+	1.0+

setMilliseconds Sets the milliseconds for a specified date according to local time.	4.0+	1.0+	4.06+	7.0+	1.0+

setMinutes Sets the minutes for a specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

setMonth Set the month for a specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

setSeconds Sets the seconds for a specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

setTime Sets the value of a Date object according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

setUTCDate Sets the day of the month for a specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

setUTCFullYear Sets the full year for a specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

setUTCHours Sets the hour for a specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

setUTCMilliseconds Sets the milliseconds for a specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

setUTCMinutes Sets the minutes for a specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

setUTCMonth Sets the month for a specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

setUTCSeconds Sets the seconds for a specified date according to universal time.	4.0+	1.0+	4.06+	7.0+	1.0+

setYear Sets the year for a specified date according to local time.	3.0+	1.0+	2.0+	7.0+	1.0+

toDateString Returns a string version of the Date object expressed in local time.	4.0+	1.0+	3.0+	7.0+	1.0+

toGMTString Converts a date to a string, using Internet GMT conventions.	4.0+	1.0+	3.0+	7.0+	1.0+

toLocaleDateString Converts a date to a string, returning the "date" portion using the current locale's conventions.	3.0+	1.0+	2.0+	7.0+	1.0+

toLocaleString Converts a date to a string, using the current locale's conventions.	3.0+	1.0+	2.0+	7.0+	1.0+

toLocaleTimeString Converts a date to a string, returning the "date" portion using the current locale's conventions.	3.0+	1.0+	2.0+	7.0+	1.0+

toSource Returns a string representing the source code of a Date object.	3.0+	1.0+	2.0+	no	no

toString Returns a string representing the specified Date object.	4.0+	1.0+	3.0+	7.0+	1.0+

toTimeString Returns a string representation of the time portion of a Date object, expressed in local time.	4.0+	1.0+	3.0+	7.0+	1.0+

toUTCString Converts a date to a string, using the universal time convention.	4.0+	1.0+	4.06+	7.0+	1.0+

UTC Accepts the same parameters as the longest form of the constructor, and returns the number of milliseconds in a Date object since January 1, 1970, 00:00:00, universal time.	3.0+	1.0+	2.0+	7.0+	1.0+

valueOf Returns the primitive value of a Date object.	4.0+	1.0+	3.0+	7.0+	1.0+
valueOf Returns the primitive value of a Date object.

Several ways to assign dates

The following examples 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);

Remarks

If you supply no arguments, the constructor creates a Date object for today's date and time according to local 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, seconds, and milliseconds.

The date is measured in milliseconds since midnight 01 January, 1970 UTC. A day holds 86,400,000 milliseconds. The Date object range is -100,000,000 days to 100,000,000 days relative to 01 January, 1970 UTC.

The Date object provides uniform behavior across platforms.

The Date object supports a number of UTC (universal) methods, as well as local time methods. UTC, also known as Greenwich Mean Time (GMT), refers to the time as set by the World Time Standard. The local time is the time known to the computer where JavaScript is executed.

For compatibility with millennium calculations (in other words, to take into account the year 2000), you should always specify the year in full; for example, use 1998, not 98. To assist you in specifying the complete year, JavaScript includes the methods getFullYear, setFullYear, getUTCFullYear, and setUTCFullYear.

The following example returns the time elapsed between timeA and timeB in milliseconds.

timeA = new Date();
// Statements here to take some action.
timeB = new Date();
timeDifference = timeB - timeA;

References

Date.parse | Date.UTC

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

Constructor Detail

Date Date([Number milliseconds,] [String dateString,] [Object yr_num, mo_num, day_num,] [Object hr_num, min_num, sec_num, ms_num])

Creates a new instance of a Date object.

Number	milliseconds	The elements to add to the front of the array. (optional)
String	dateString	String value representing a date. The string should be in a format recognized by the parse method. (optional)
Object	yr_num, mo_num, day_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. (optional)
Object	hr_num, min_num, sec_num, ms_num	Integer values representing part of a date. (optional)

Property Detail

Function constructor

Specifies the function that creates an object's prototype. Note that the value of this property is a reference to the function itself, not a string containing the function's name.

See Also

Object.constructor

Availability

JavaScript 1.1 | NES 2.0 | ECMA-262

Date prototype

Represents the prototype for this class. You can use the prototype to add properties or methods to all instances of a class.

See Also

Function.prototype

Availability

JavaScript 1.1 | NES 2.0 | ECMA-262

Method Detail

getDate() : Number

Returns the day of the month for the specified date according to local time.

Using `getDate`

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()

Remarks

The value returned by getDate is an integer between 1 and 31.

See Also

getUTCDate | getUTCDay | setDate

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

getDay() : Number

Returns a number representing the day of the week for the specified date (according to local time).

Using `getDay`

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();

Remarks

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.

See Also

getUTCDay | setDate

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

getFullYear() : Number

Returns the year of the specified date according to local time.

Using `getFullYear`

The following example assigns the four-digit value of the current year to the variable yr.

var yr;
Today = new Date();
yr = Today.getFullYear();

theBigDay = new Date("July 1, 1999")
sameAsBigDay = new Date()
sameAsBigDay.setTime(theBigDay.getTime())

Remarks

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.

This method is functionally equivalent to the valueOf method.

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

getTimezoneOffset() : Number

Returns the time-zone offset in minutes for the current locale.

Using `getTimezoneOffset`

x = new Date()
currentTimeZoneOffsetInHours = x.getTimezoneOffset()/60

Remarks

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.

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

getUTCDate() : Number

Returns the day (date) of the month in the specified date according to universal time.

Using `getUTCDate`

The following example assigns the day portion of the current date to the variable d.

var d;
Today = new Date();
d = Today.getUTCDate();

Remarks

The value returned by getUTCDate is an integer between 1 and 31.

See Also

getDate | getUTCDay | setUTCDate

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getUTCDay() : Number

Returns the day of the week in the specified date according to universal time.

Using `getUTCDay`

The following example assigns the weekday portion of the current date to the variable weekday.

var weekday;
Today = new Date()
weekday = Today.getUTCDay()

Remarks

The value returned by getUTCDay is an integer corresponding to the day of the week: 0 for Sunday, 1 for Monday, 2 for Tuesday, and so on.

See Also

getDay | getUTCDate | setUTCDate

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getUTCFullYear() : Number

Returns the year in the specified date according to universal time.

Using `getUTCFullYear`

The following example assigns the four-digit value of the current year to the variable yr.

var yr;
Today = new Date();
yr = Today.getUTCFullYear();

Remarks

The value returned by getUTCFullYear is an absolute number that is compliant with year-2000, for example, 1995.

See Also

getFullYear | setFullYear

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getUTCHours() : Number

Returns the hours in the specified date according to universal time.

Using `getUTCHours`

The following example assigns the hours portion of the current time to the variable hrs.

var hrs;
Today = new Date();
hrs = Today.getUTCHours();

Remarks

The value returned by getUTCHours is an integer between 0 and 23.

See Also

getHours | setUTCHours

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getUTCMilliseconds() : Number

Returns the milliseconds in the specified date according to universal time.

Using `getUTCMilliseconds` =

The following example assigns the milliseconds portion of the current time to the variable ms.

var ms;
Today = new Date();
ms = Today.getUTCMilliseconds();

Remarks

The value returned by getUTCMilliseconds is an integer between 0 and 999.

See Also

getMilliseconds | setUTCmilliseconds

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getUTCMinutes() : Number

Returns the minutes in the specified date according to universal time.

Using `getUTCMinutes`

The following example assigns the minutes portion of the current time to the variable min.

var min;
Today = new Date();
min = Today.getUTCMinutes();

Remarks

The value returned by getUTCMinutes is an integer between 0 and 59.

See Also

getMinutes | setUTCMinutes

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getUTCMonth() : Number

Returns the month of the specified date according to universal time.

Using `getUTCMonth`

The following example assigns the month portion of the current date to the variable mon.

var mon;
Today = new Date();
mon = Today.getUTCMonth();

Remarks

The value returned by getUTCMonth is an integer between 0 and 11 corresponding to the month. 0 for January, 1 for February, 2 for March, and so on.

See Also

getMonth | setUTCMonth

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getUTCSeconds() : Number

Returns the seconds in the specified date according to universal time.

Using `getUTCSeconds`

The following example assigns the seconds portion of the current time to the variable sec.

var sec;
Today = new Date();
sec = Today.getUTCSeconds();

Remarks

The value returned by getUTCSeconds is an integer between 0 and 59.

See Also

getSeconds | setUTCSeconds

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

getYear() : Number

Returns the year in the specified date according to local time.

Years between 1900 and 1999

The second statement assigns the value 95 to the variable year.

Xmas = new Date("December 25, 1995 23:15:00")
year = Xmas.getYear() // returns 95

Years above 1999

The second statement assigns the value 100 to the variable year.

Xmas = new Date("December 25, 2000 23:15:00")
year = Xmas.getYear() // returns 100

Years below 1900

The second statement assigns the value -100 to the variable year.

Xmas = new Date("December 25, 1800 23:15:00")
year = Xmas.getYear() // returns -100

Setting and getting a year between 1900 and 1999

The second statement assigns the value 95 to the variable year, representing the year 1995.

Xmas.setYear(95)
year = Xmas.getYear() // returns 95

Remarks

getYear is no longer used and has been replaced by the getFullYear method.

The getYear method returns the year minus 1900; thus:

For years above 2000, the value returned by getYear is 100 or greater. For example, if the year is 2026, getYear returns 126.

For years between and including 1900 and 1999, the value returned by getYear is between 0 and 99. For example, if the year is 1976, getYear returns 76.

For years less than 1900 or greater than 1999, the value returned by getYear is less than 0. For example, if the year is 1800, getYear returns -100.

To take into account years before and after 2000, you should use getFullYear instead of getYear so that the year is specified in full.

See Also

getFullYear | getUTCFullYear | setYear

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1 | deprecated by ECMAScript v3

now() : Number

Returns the number of milliseconds passed since 1970-01-01 00:00:00 UTC.

Remarks

SpiderMonkey extension to ECMAScript standard. Supported by Mozilla only.

Availability

parse(String dateString) : static Number

Parses a string representation of a date, and returns the number of milliseconds since January 1, 1970, 00:00:00, local time.

String

dateString

A string representing a date.

Using `parse`

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")) ;

Remarks

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 syntax: "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.

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

setDate(Number dayValue) : Number

Sets the day of the month for a specified date according to local time.

Number

dayValue

An integer from 1 to 31, representing the day of the month.

Using `setDate`

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)

Remarks

Before this method was standardized to ECMAScript, it returned nothing.

See Also

getDate | setUTCDate

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

setFullYear(Number yearValue, [Number monthValue,] [Number dayValue]) : Number

Sets the full year for a specified date according to local time.

Number	yearValue	An integer specifying the numeric value of the year, for example, 1995.
Number	monthValue	An integer between 0 and 11 representing the months January through December. (optional)
Number	dayValue	An integer between 1 and 31 representing the day of the month. If you specify the dayValue parameter, you must also specify the monthValue. (optional)

Using `setFullYear`

theBigDay = new Date();
theBigDay.setFullYear(1997);

Remarks

If you do not specify the monthValue and dayValue parameters, the values returned from the getMonth and getDate methods are used.

If a parameter you specify is outside of the expected range, setFullYear attempts to update the other parameters and the date information in the Date object accordingly. For example, if you specify 15 for monthValue, the year is incremented by 1 (year + 1), and 3 is used for the month.

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setHours(Number hoursValue, [Number minutesValue,] [Number secondsValue,] [Number msValue]) : Number

Sets the hours for a specified date according to local time.

Number	hoursValue	An integer between 0 and 23, representing the hour.
Number	minutesValue	An integer between 0 and 59, representing the minutes. (optional)
Number	secondsValue	An integer between 0 and 59, representing the seconds. If you specify the secondsValue parameter, you must also specify the minutesValue. (optional)
Number	msValue	A number between 0 and 999, representing the milliseconds. If you specify the msValue parameter, you must also specify the minutesValue and secondsValue. (optional)

Using `setHours`

theBigDay.setHours(7)

Remarks

Before this method was standardized to ECMAScript, it returned nothing. If you do not specify the minutesValue, secondsValue, and msValue parameters, the values returned from the getUTCMinutes, getUTCSeconds, and getMilliseconds methods are used.

If a parameter you specify is outside of the expected range, setHours attempts to update the date information in the Date object accordingly. For example, if you use 100 for secondsValue, the minutes will be incremented by 1 (min + 1), and 40 will be used for seconds.

See Also

getHours | setUTCHours

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

setMilliseconds(Number millisecondsValue) : Number

Sets the milliseconds for a specified date according to local time.

Number

millisecondsValue

A number between 0 and 999, representing the milliseconds.

Using `setMilliseconds`

theBigDay = new Date();
theBigDay.setMilliseconds(100);

Remarks

If you specify a number outside the expected range, the date information in the Date object is updated accordingly. For example, if you specify 1005, the number of seconds is incremented by 1, and 5 is used for the milliseconds.

See Also

getMilliseconds | setUTCMilliseconds

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setMinutes(Number minutesValue, [Number secondsValue,] [Number msValue]) : Number

Sets the minutes for a specified date according to local time.

Number	minutesValue	An integer between 0 and 59, representing the minutes.
Number	secondsValue	An integer between 0 and 59, representing the seconds. If you specify the secondsValue parameter, you must also specify the minutesValue. (optional)
Number	msValue	A number between 0 and 999, representing the milliseconds. If you specify the msValue parameter, you must also specify the minutesValue and secondsValue. (optional)

Using `setMinutes`

theBigDay.setMinutes(45)

Remarks

Before this method was standardized to ECMAScript, it returned nothing. If you do not specify the secondsValue and msValue parameters, the values returned from getSeconds and getMilliseconds methods are used.

If a parameter you specify is outside of the expected range, setMinutes attempts to update the date information in the Date object accordingly. For example, if you use 100 for secondsValue, the minutes (minutesValue) will be incremented by 1 (minutesValue + 1), and 40 will be used for seconds.

See Also

getMinutes | setUTCMinutes

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

setMonth(Number monthValue, [Number dayValue]) : Number

Set the month for a specified date according to local time.

Number	monthValue	An integer between 0 and 11 (representing the months January through December).
Number	dayValue	An integer from 1 to 31, representing the day of the month. (optional)

Using `setMonth`

theBigDay.setMonth(6)

Remarks

Before this method was standardized to ECMAScript, it returned nothing. If you do not specify the dayValue parameter, the value returned from the getDate method is used.

If a parameter you specify is outside of the expected range, setMonth attempts to update the date information in the Date object accordingly. For example, if you use 15 for monthValue, the year will be incremented by 1 (year + 1), and 3 will be used for month.

See Also

getMonth | setUTCMonth

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

setSeconds(Number secondsValue, [Number msValue]) : Number

Sets the seconds for a specified date according to local time.

Number	secondsValue	An integer between 0 and 59.
Number	msValue	A number between 0 and 999, representing the milliseconds. (optional)

Using `setSeconds`

theBigDay.setSeconds(30)

Remarks

Before this method was standardized to ECMAScript, it returned nothing. If you do not specify the msValue parameter, the value returned from the getMilliseconds method is used.

If a parameter you specify is outside of the expected range, setSeconds attempts to update the date information in the Date object accordingly. For example, if you use 100 for secondsValue, the minutes stored in the Date object will be incremented by 1, and 40 will be used for seconds.

See Also

getSeconds | setUTCSeconds

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

setTime(Number timeValue) : Number

Sets the value of a Date object according to local time.

Number

timeValue

An integer representing the number of milliseconds since 1 January 1970, 00:00:00.

Using `setTime`

theBigDay = new Date("July 1, 1999")
sameAsBigDay = new Date();
sameAsBigDay.setTime(theBigDay.getTime());

Remarks

Before this method was standardized to ECMAScript, it returned nothing. Use the setTime method to help assign a date and time to another Date object.

See Also

getTime | setUTCHours

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

setUTCDate(Number dayValue) : Number

Sets the day of the month for a specified date according to universal time.

Number

dayValue

An integer from 1 to 31, representing the day of the month.

Using `setUTCDate`

theBigDay = new Date();
theBigDay.setUTCDate(20);

Remarks

If a parameter you specify is outside of the expected range, setUTCDate attempts to update the date information in the Date object accordingly. For example, if you use 40 for dayValue, and the month stored in the Date object is June, the day will be changed to 10 and the month will be incremented to July.

See Also

getUTCDate | setDate

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setUTCFullYear(Number yearValue, [Number monthValue,] [Number dayValue]) : Number

Sets the full year for a specified date according to universal time.

Number	yearValue	An integer specifying the numeric value of the year, for example, 1995.
Number	monthValue	An integer between 0 and 11 representing the months January through December. (optional)
Number	dayValue	An integer between 1 and 31 representing the day of the month. If you specify the dayValue parameter, you must also specify the monthValue. (optional)

Using `setUTCFullYear`

theBigDay = new Date();
theBigDay.setUTCFullYear(1997);

Remarks

If you do not specify the monthValue and dayValue parameters, the values returned from the getMonth and getDate methods are used.

If a parameter you specify is outside of the expected range, setUTCFullYear attempts to update the other parameters and the date information in the Date object accordingly. For example, if you specify 15 for monthValue, the year is incremented by 1 (year + 1), and 3 is used for the month.

See Also

getUTCFullYear | setFullYear

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setUTCHours(Number hoursValue, [Number minutesValue,] [Number secondsValue,] [Number msValue]) : Number

Sets the hour for a specified date according to universal time.

Number	hoursValue	An integer between 0 and 23, representing the hour.
Number	minutesValue	An integer between 0 and 59, representing the minutes. (optional)
Number	secondsValue	An integer between 0 and 59, representing the seconds. If you specify the secondsValue parameter, you must also specify the minutesValue. (optional)
Number	msValue	A number between 0 and 999, representing the milliseconds. If you specify the msValue parameter, you must also specify the minutesValue and secondsValue. (optional)

Using `setUTCHours`

theBigDay = new Date();
theBigDay.setUTCHours(8);

Remarks

If you do not specify the minutesValue, secondsValue, and msValue parameters, the values returned from the getUTCMinutes, getUTCSeconds, and getUTCMilliseconds methods are used.

If a parameter you specify is outside of the expected range, setUTCHours attempts to update the date information in the Date object accordingly. For example, if you use 100 for secondsValue, the minutes will be incremented by 1 (min + 1), and 40 will be used for seconds.

See Also

getUTCHours | setHours

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setUTCMilliseconds(Number millisecondsValue) : Number

Sets the milliseconds for a specified date according to universal time.

Number

millisecondsValue

A number between 0 and 999, representing the milliseconds.

Using `setUTCMilliseconds`

theBigDay = new Date();
theBigDay.setUTCMilliseconds(500);

Remarks

If a parameter you specify is outside of the expected range, setUTCMilliseconds attempts to update the date information in the Date object accordingly. For example, if you use 1100 for millisecondsValue, the seconds stored in the Date object will be incremented by 1, and 100 will be used for milliseconds.

See Also

getUTCMilliseconds | setMilliseconds

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setUTCMinutes(Number minutesValue, [Number secondsValue,] [Number msValue]) : Number

Sets the minutes for a specified date according to universal time.

Number	minutesValue	An integer between 0 and 59, representing the minutes.
Number	secondsValue	An integer between 0 and 59, representing the seconds. If you specify the secondsValue parameter, you must also specify the minutesValue. (optional)
Number	msValue	A number between 0 and 999, representing the milliseconds. If you specify the msValue parameter, you must also specify the minutesValue and secondsValue. (optional)

Using `setUTCMinutes`

theBigDay = new Date();
theBigDay.setUTCMinutes(43);

Remarks

If you do not specify the secondsValue and msValue parameters, the values returned from getUTCSeconds and getUTCMilliseconds methods are used.

If a parameter you specify is outside of the expected range, setUTCMinutes attempts to update the date information in the Date object accordingly. For example, if you use 100 for secondsValue, the minutes (minutesValue) will be incremented by 1 (minutesValue + 1), and 40 will be used for seconds.

See Also

getUTCMinutes | setMinutes

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setUTCMonth(Number monthValue, [Number dayValue]) : Number

Sets the month for a specified date according to universal time.

Number	monthValue	An integer between 0 and 11, representing the months January through December.
Number	dayValue	An integer from 1 to 31, representing the day of the month. (optional)

Using `setUTCMonth`

theBigDay = new Date();
theBigDay.setUTCMonth(11);

Remarks

If you do not specify the dayValue parameter, the value returned from the getUTCDate method is used.

If a parameter you specify is outside of the expected range, setUTCMonth attempts to update the date information in the Date object accordingly. For example, if you use 15 for monthValue, the year will be incremented by 1 (year + 1), and 3 will be used for month.

See Also

getUTCMonth | setMonth

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setUTCSeconds(Number secondsValue, [Number msValue]) : Number

Sets the seconds for a specified date according to universal time.

Number	secondsValue	An integer between 0 and 59.
Number	msValue	A number between 0 and 999, representing the milliseconds. (optional)

Using `setUTCSeconds`

theBigDay = new Date();
theBigDay.setUTCSeconds(20);

Remarks

If you do not specify the msValue parameter, the value returned from the getUTCMilliseconds methods is used.

If a parameter you specify is outside of the expected range, setUTCSeconds attempts to update the date information in the Date object accordingly. For example, if you use 100 for secondsValue, the minutes stored in the Date object will be incremented by 1, and 40 will be used for seconds.

See Also

getUTCSeconds | setSeconds

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

setYear(Number yearValue) : Number

Sets the year for a specified date according to local time.

Number

yearValue

An integer.

Using `setYear`

The first two lines set the year to 1996. The third sets the year to 2000.

theBigDay.setYear(96)
theBigDay.setYear(1996)
theBigDay.setYear(2000)

Remarks

Before this method was standardized to ECMAScript, it returned nothing. setYear is no longer used and has been replaced by the setFullYear method.

If yearValue</code. is a number between 0 and 99 (inclusive), then the year for <code>dateObjectName is set to 1900 + yearValue. Otherwise, the year for dateObjectName is set to yearValue.

To take into account years before and after 2000, you should use setFullYear instead of setYear so that the year is specified in full.

See Also

getYear | setFullYear | setUTCFullYear

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1 | deprecated by ECMAScript v3

toDateString() : String

Returns a string version of the Date object expressed in local time.

Availability

JavaScript 1.5 | JScript 5.5 | ECMAScript v3

toGMTString() : String

Converts a date to a string, using Internet GMT conventions.

Using `toGMTString`

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

Remarks

toGMTString is no longer used and has been replaced by the toUTCString method.

The exact format of the value returned by toGMTString varies according to the platform.

You should use Date.toUTCString instead of toGMTSTring.

See Also

Date.toUTCString | toLocaleString

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1 | deprecated by ECMAScript v3

toLocaleDateString() : String

Converts a date to a string, returning the "date" portion using the current locale's conventions.

Using `toLocaleDateString`

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.toLocaleDateString()

In this example, toLocaleDateString returns a string value that is similar to the following form. The exact format depends on the platform.

12/18/95

Remarks

The toLocaleDateString method relies on the underlying operating system in formatting dates. It converts the date to a string using the formatting convention of the operating system where the script is running. For example, in the United States, the month appears before the date (04/15/98), whereas in Germany the date appears before the month (15.04.98). If the operating system is not year-2000 compliant and does not use the full year for years before 1900 or over 2000, toLocaleDateString returns a string that is not year-2000 compliant. toLocaleDateString behaves similarly to toString when converting a year that the operating system does not properly format.

Methods such as getHours, getMinutes, and getSeconds give more portable results than toLocaleDateString.

Availability

JavaScript 1.5 | JScript 5.5 | ECMAScript v3

toLocaleString() : String

Converts a date to a string, using the current locale's conventions.

Using `toLocaleString`

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

Remarks

The toLocaleString method relies on the underlying operating system in formatting dates. It converts the date to a string using the formatting convention of the operating system where the script is running. For example, in the United States, the month appears before the date (04/15/98), whereas in Germany the date appears before the month (15.04.98). If the operating system is not year-2000 compliant and does not use the full year for years before 1900 or over 2000, toLocaleString returns a string that is not year-2000 compliant. toLocaleString behaves similarly to toString when converting a year that the operating system does not properly format.

Methods such as getHours, getMinutes, and getSeconds give more portable results than toLocaleString.

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

toLocaleTimeString() : String

Converts a date to a string, returning the "date" portion using the current locale's conventions.

Using `toLocaleTimeString`

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.toLocaleTimeString()

In this example, toLocaleTimeString returns a string value that is similar to the following form. The exact format depends on the platform.

17:28:35

Remarks

The toLocaleTimeString method relies on the underlying operating system in formatting dates. It converts the date to a string using the formatting convention of the operating system where the script is running. For example, in the United States, the month appears before the date (04/15/98), whereas in Germany the date appears before the month (15.04.98). If the operating system is not year-2000 compliant and does not use the full year for years before 1900 or over 2000, toLocaleTimeString returns a string that is not year-2000 compliant. toLocaleTimeString behaves similarly to toString when converting a year that the operating system does not properly format.

Methods such as getHours, getMinutes, and getSeconds give more portable results than toLocaleTimeString.

Availability

JavaScript 1.5 | JScript 5.5 | ECMAScript v3

toSource() : String

Returns a string representing the source code of a Date object.

Remarks

The toSource method returns the following values:

For the built-in Date object, toSource returns the following string indicating that the source code is not available:

function Date() {
   [native code]
}

For instances of Date, toSource returns a string representing the source code.

This method is usually called internally by JavaScript and not explicitly in code.

See Also

Object.toSource

Availability

JavaScript 1.3 | ECMAScript v1

toString() : String

Returns a string representing the specified Date object.

Using `toString`

The following assigns the toString value of a Date object to myVar:

x = new Date();
myVar=x.toString();   //assigns a value to myVar similar to:
     //Mon Sep 28 14:36:22 GMT-0700 (Pacific Daylight Time) 1998

Remarks

The Date object overrides the toString method of the Object object; it does not inherit Object.toString. For Date objects, the toString method returns a string representation of the object.

JavaScript calls the toString method automatically when a date is to be represented as a text value or when a date is referred to in a string concatenation.

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1 Overrides Object.toString

toTimeString() : String

Returns a string representation of the time portion of a Date object, expressed in local time.

Availability

JavaScript 1.5 | JScript 5.5 | ECMAScript v3

toUTCString() : String

Converts a date to a string, using the universal time convention.

Using `toUTCString`

var UTCstring;
Today = new Date();
UTCstring = Today.toUTCString();

Remarks

The value returned by toUTCString is a readable string formatted according to UTC convention. The format of the return value may vary according to the platform.

See Also

Date.toLocaleString | Date.toString

Availability

JavaScript 1.2 | JScript 3.0 | ECMAScript v1

UTC(Object year, Number month, [Number date,] [Number hrs,] [Number min,] [Number sec,] [Number ms]) : static Number

Accepts the same parameters as the longest form of the constructor, and returns the number of milliseconds in a Date object since January 1, 1970, 00:00:00, universal time.

Object	year	A year after 1900.
Number	month	An integer between 0 and 11 representing the month.
Number	date	An integer between 1 and 31 representing the day of the month. (optional)
Number	hrs	An integer between 0 and 23 representing the hours. (optional)
Number	min	An integer between 0 and 59 representing the minutes. (optional)
Number	sec	An integer between 0 and 59 representing the seconds. (optional)
Number	ms	An integer between 0 and 999 representing the milliseconds. (optional)

Using `Date.UTC`

The following statement creates a Date object using GMT instead of local time:

gmtDate = new Date(Date.UTC(96, 11, 1, 0, 0, 0));

Remarks

UTC takes comma-delimited date parameters and returns the number of milliseconds between January 1, 1970, 00:00:00, universal time and the time you specified.

You should specify a full year for the year; for example, 1998. If a year between 0 and 99 is specified, the method converts the year to a year in the 20th century (1900 + year); for example, if you specify 95, the year 1995 is used.

The UTC method differs from the Date constructor in two ways.

Date.UTC uses universal time instead of the local time.

Date.UTC returns a time value as a number instead of creating a Date object.

If a parameter you specify is outside of the expected range, the UTC method updates the other parameters to allow for your number. For example, if you use 15 for month, the year will be incremented by 1 (year + 1), and 3 will be used for the month.

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.

See Also

Date | Date.parse | Date.setTime

Availability

JavaScript 1.0 | JScript 1.0 | ECMAScript v1

valueOf() : Number

Returns the primitive value of a Date object.

Using `valueOf`

x = new Date(56, 6, 17);
myVar = x.valueOf();      //assigns -424713600000 to myVar

Remarks

The valueOf method returns the primitive value of a Date object as a number data type, the number of milliseconds since midnight 01 January, 1970 UTC.

This method is functionally equivalent to the getTime method.

This method is usually called internally by JavaScript and not explicitly in code.

See Also

Object.valueOf | getTime

Availability

JavaScript 1.1 | ECMAScript v1