Date
Lets you work with dates and times.
Created by
The Date constructor:
new Date()
new Date(milliseconds)
new Date(dateString)
new Date(yr_num, mo_num, day_num
[, hr_num, min_num, sec_num, ms_num])
Versions prior to JavaScript 1.3:
new Date()
new Date(milliseconds)
new Date(dateString)
new Date(yr_num, mo_num, day_num[, hr_num, min_num, sec_num])
Parameters
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milliseconds
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Integer value representing the number of milliseconds since 1 January 1970 00:00:00.
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dateString
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String value representing a date. The string should be in a format recognized by the Date.parse method.
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yr_num, mo_num,
day_num
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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.
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hr_num, min_num,
sec_num, ms_num
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Integer values representing part of a date.
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Description
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, getFullUTCYear, and setFullUTCYear.
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;
Backward Compatibility
JavaScript 1.2 and earlier. The Date object behaves as follows:
-
-
Dates prior to 1970 are not allowed.
-
JavaScript depends on platform-specific date facilities and behavior; the behavior of the Date object varies from platform to platform.
Property Summary
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Property
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Description
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constructor
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Specifies the function that creates an object's prototype.
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prototype
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Allows the addition of properties to a Date object.
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Method Summary
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Method
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Description
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getDate
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Returns the day of the month for the specified date according to local time.
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getDay
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Returns the day of the week for the specified date according to local time.
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getFullYear
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Returns the year of the specified date according to local time.
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getHours
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Returns the hour in the specified date according to local time.
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getMilliseconds
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Returns the milliseconds in the specified date according to local time.
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getMinutes
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Returns the minutes in the specified date according to local time.
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getMonth
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Returns the month in the specified date according to local time.
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getSeconds
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Returns the seconds in the specified date according to local time.
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getTime
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Returns the numeric value corresponding to the time for the specified date according to local time.
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getTimezoneOffset
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Returns the time-zone offset in minutes for the current locale.
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getUTCDate
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Returns the day (date) of the month in the specified date according to universal time.
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getUTCDay
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Returns the day of the week in the specified date according to universal time.
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getUTCFullYear
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Returns the year in the specified date according to universal time.
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getUTCHours
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Returns the hours in the specified date according to universal time.
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getUTCMilliseconds
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Returns the milliseconds in the specified date according to universal time.
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getUTCMinutes
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Returns the minutes in the specified date according to universal time.
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getUTCMonth
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Returns the month according in the specified date according to universal time.
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getUTCSeconds
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Returns the seconds in the specified date according to universal time.
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getYear
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Returns the year in the specified date according to local time.
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parse
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Returns the number of milliseconds in a date string since January 1, 1970, 00:00:00, local time.
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setDate
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Sets the day of the month for a specified date according to local time.
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setFullYear
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Sets the full year for a specified date according to local time.
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setHours
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Sets the hours for a specified date according to local time.
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setMilliseconds
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Sets the milliseconds for a specified date according to local time.
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setMinutes
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Sets the minutes for a specified date according to local time.
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setMonth
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Sets the month for a specified date according to local time.
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setSeconds
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Sets the seconds for a specified date according to local time.
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setTime
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Sets the value of a Date object according to local time.
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setUTCDate
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Sets the day of the month for a specified date according to universal time.
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setUTCFullYear
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Sets the full year for a specified date according to universal time.
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setUTCHours
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Sets the hour for a specified date according to universal time.
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setUTCMilliseconds
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Sets the milliseconds for a specified date according to universal time.
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setUTCMinutes
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Sets the minutes for a specified date according to universal time.
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setUTCMonth
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Sets the month for a specified date according to universal time.
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setUTCSeconds
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Sets the seconds for a specified date according to universal time.
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setYear
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Sets the year for a specified date according to local time.
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toGMTString
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Converts a date to a string, using the Internet GMT conventions.
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toLocaleString
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Converts a date to a string, using the current locale's conventions.
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toLocaleDateString
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Returns the "date" portion of the Date as a string, using the current locale's conventions.
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toLocaleTimeString
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Returns the "time" portion of the Date as a string, using the current locale's conventions.
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toSource
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Returns an object literal representing the specified Date object; you can use this value to create a new object. Overrides the Object.toSource method.
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toString
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Returns a string representing the specified Date object. Overrides the Object.toString method.
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toUTCString
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Converts a date to a string, using the universal time convention.
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UTC
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Returns the number of milliseconds in a Date object since January 1, 1970, 00:00:00, universal time.
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valueOf
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Returns the primitive value of a Date object. Overrides the Object.valueOf method.
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In addition, this object inherits the watch and unwatch methods from Object.
Examples
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)
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.
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Property of
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Date
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Implemented in
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JavaScript 1.1, NES 2.0
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ECMA version
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ECMA-262
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Description
See Object.constructor.
getDate
Returns the day of the month for the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getDate()
Parameters
None
Description
The value returned by getDate is an integer between 1 and 31.
Examples
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()
See also
Date.getUTCDate, Date.getUTCDay, Date.setDate
getDay
Returns the day of the week for the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getDay()
Parameters
None
Description
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.
Examples
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()
See also
Date.getUTCDay, Date.setDate
getFullYear
Returns the year of the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.3
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ECMA version
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ECMA-262
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Syntax
getFullYear()
Parameters
None
Description
The value returned by getFullYear is an absolute number. For dates between the years 1000 and 9999, getFullYear returns a four-digit number, for example, 1995. Use this function to make sure a year is compliant with years after 2000.
Use this method instead of the getYear method.
Examples
The following example assigns the four-digit value of the current year to the variable yr.
var yr;
Today = new Date();
yr = Today.getFullYear();
See also
Date.getYear, Date.getUTCFullYear , Date.setFullYear
getHours
Returns the hour for the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getHours()
Parameters
None
Description
The value returned by getHours is an integer between 0 and 23.
Examples
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()
See also
Date.getUTCHours, Date.setHours
getMilliseconds
Returns the milliseconds in the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.3
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ECMA version
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ECMA-262
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Syntax
getMilliseconds()
Parameters
None
Description
The value returned by getMilliseconds is a number between 0 and 999.
Examples
The following example assigns the milliseconds portion of the current time to the variable ms.
var ms;
Today = new Date();
ms = Today.getMilliseconds();
See also
Date.getUTCMilliseconds , Date.setMilliseconds
getMinutes
Returns the minutes in the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getMinutes()
Parameters
None
Description
The value returned by getMinutes is an integer between 0 and 59.
Examples
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()
See also
Date.getUTCMinutes, Date.setMinutes
getMonth
Returns the month in the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getMonth()
Parameters
None
Description
The value returned by getMonth is an integer between 0 and 11. 0 corresponds to January, 1 to February, and so on.
Examples
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()
See also
Date.getUTCMonth, Date.setMonth
getSeconds
Returns the seconds in the current time according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getSeconds()
Parameters
None
Description
The value returned by getSeconds is an integer between 0 and 59.
Examples
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()
See also
Date.getUTCSeconds, Date.setSeconds
getTime
Returns the numeric value corresponding to the time for the specified date according to local time.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getTime()
Parameters
None
Description
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.
Examples
The following example assigns the date value of theBigDay to sameAsBigDay:
theBigDay = new Date("July 1, 1999")
sameAsBigDay = new Date()
sameAsBigDay.setTime(theBigDay.getTime())
See also
Date.getUTCHours, Date.setTime
getTimezoneOffset
Returns the time-zone offset in minutes for the current locale.
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Method of
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Date
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Implemented in
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JavaScript 1.0, NES 2.0
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ECMA version
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ECMA-262
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Syntax
getTimezoneOffset()
Parameters
None
Description
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.
Examples
x = new Date()
currentTimeZoneOffsetInHours = x.getTimezoneOffset()/60
getUTCDate
Returns the day (date) of the month in the specified date according to universal time.
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Method of
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Date
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Implemented in
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JavaScript 1.3
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ECMA version
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ECMA-262
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Syntax
getUTCDate()
Parameters
None
Description
The value returned by getUTCDate is an integer between 1 and 31.
Examples
The following example assigns the day portion of the current date to the variable d.
var d;
Today = new Date();
d = Today.getUTCDate();
See also
Date.getDate , Date.getUTCDay , Date.setUTCDate
getUTCDay
Returns the day of the week in the specified date according to universal time.
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Method of
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Date
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Implemented in
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JavaScript 1.3
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ECMA version
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ECMA-262
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Syntax
getUTCDay()
Parameters
None
Description
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.
Examples
The following example assigns the weekday portion of the current date to the variable ms.
var weekday;
Today = new Date()
weekday = Today.getUTCDay()
See also
Date.getDay , Date.getUTCDate , Date.setUTCDate
getUTCFullYear
Returns the year in the specified date according to universal time.
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Method of
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Date
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Implemented in
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JavaScript 1.3
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ECMA version
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ECMA-262
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Syntax
getUTCFullYear()
Parameters
None
Description
The value returned by getUTCFullYear is an absolute number that is compliant with year-2000, for example, 1995.
Examples
The following example assigns the four-digit value of the current year to the variable yr.
var yr;
Today = new Date();
yr = Today.getUTCFullYear();
See also
Date.getFullYear , Date.setFullYear
getUTCHours
Returns the hours in the specified date according to universal time.
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Method of
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Date
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Implemented in
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JavaScript 1.3
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ECMA version
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ECMA-262
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Syntax
getUTCHours()
Parameters
None
Description
The value returned by getUTCHours is an integer between 0 and 23.
Examples
The following example assigns the hours portion of the current time to the variable hrs.
var hrs;
Today = new Date();
hrs = Today.getUTCHours();
See also
Date.getHours , Date.setUTCHours
getUTCMilliseconds
Returns the milliseconds in the specified date according to universal time.
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Method of
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Date
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Implemented in
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JavaScript 1.3
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ECMA version
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ECMA-262
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Syntax
getUTCMilliSeconds()
Parameters
None
Description
The value returned by getUTCMilliseconds is an integer between 0 and 999.
Examples
The following example assigns the milliseconds portion of the current time to the variable ms.
var ms;
Today = new Date();
ms = Today.getUTCMilliseconds();
See also
Date.getMilliseconds , Date.setUTCMilliseconds
getUTCMinutes
Returns the minutes in the specified date according to universal time.
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Method of
|
Date
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Implemented in
|
JavaScript 1.3
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ECMA version
|
ECMA-262
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Syntax
getUTCMinutes()
Parameters
None
Description
The value returned by getUTCMinutes is an integer between 0 and 59.
Examples
The following example assigns the minutes portion of the current time to the variable min.
var min;
Today = new Date();
min = Today.getUTCMinutes();
See also
Date.getMinutes , Date.setUTCMinutes
getUTCMonth
Returns the month according in the specified date according to universal time.
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Method of
|
Date
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Implemented in
|
JavaScript 1.3
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ECMA version
|
ECMA-262
|
Syntax
getUTCMonth()
Parameters
None
Description
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.
Examples
The following example assigns the month portion of the current date to the variable mon.
var mon;
Today = new Date();
mon = Today.getUTCMonth();
See also
Date.getMonth , Date.setUTCMonth
font face="Arial, Helvetica, sans-serif" size= "4">getUTCSeconds
Returns the seconds in the specified date according to universal time.
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Method of
|
Date
|
|
Implemented in
|
JavaScript 1.3
|
|
ECMA version
|
ECMA-262
|
Syntax
getUTCSeconds()
Parameters
None
Description
The value returned by getUTCSeconds is an integer between 0 and 59.
Examples
The following example assigns the seconds portion of the current time to the variable sec.
var sec;
Today = new Date();
sec = Today.getUTCSeconds();
See also
Date.getSeconds , Date.setUTCSeconds
getYear
Returns the year in the specified date according to local time.
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Method of
|
Date
|
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Implemented in
|
JavaScript 1.0, NES 2.0
JavaScript 1.3: deprecated; also, getYear returns the year minus 1900 regardless of the year specified
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ECMA version
|
ECMA-262
|
Syntax
getYear()
Parameters
None
Description
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 Date.getFullYear instead of getYear so that the year is specified in full.
Backward Compatibility
JavaScript 1.2 and earlier versions. 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.
Examples
Example 1. 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
Example 2. 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
Example 3. 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
Example 4. The second statement assigns the value 95 to the variable year, representing the year 1995.
Xmas.setYear(95)
year = Xmas.getYear() // returns 95
See also
Date.getFullYear, Date.getUTCFullYear, Date.setYear
parse
Returns the number of milliseconds in a date string since January 1, 1970, 00:00:00, local time.
|
Method of
|
Date
|
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Static
|
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Implemented in
|
JavaScript 1.0, NES 2.0
|
|
ECMA version
|
ECMA-262
|
Syntax
Date.parse(dateString)
Parameters
:
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dateString
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A string representing a date.
|
Description
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.
Examples
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"))
See also
Date.UTC
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.
|
Property of
|
Date
|
|
Implemented in
|
JavaScript 1.1, NES 2.0
|
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ECMA version
|
ECMA-262
|
setDate
Sets the day of the month for a specified date according to local time.
|
Method of
|
Date
|
|
Implemented in
|
JavaScript 1.0, NES 2.0
|
|
ECMA version
|
ECMA-262
|
Syntax
setDate(dayValue)
Parameters
|
dayValue
|
An integer from 1 to 31, representing the day of the month.
|
Examples
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)
See also
Date.getDate, Date.setUTCDate
setFullYear
Sets the full year for a specified date according to local time.
|
Method of
|
Date
|
|
Implemented in
|
JavaScript 1.3
|
|
ECMA version
|
ECMA-262
|
Syntax
setFullYear(yearValue[, monthValue[, dayValue]])
Parameters
|
yearValue
|
An integer specifying the numeric value of the year, for example, 1995.
|
|
monthValue
|
An integer between 0 and 11 representing the months January through December.
|
|
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.
|
Description
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.
Examples
theBigDay = new Date();
theBigDay.setFullYear(1997);
See also
Date.getUTCFullYear ,Date.setUTCFullYear, Date.setYear
setHours
Sets the hours for a specified date according to local time.
