From 4b1a9203c547c019fc5398082ae19a3f3d4c3efe Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:41:15 -0500 Subject: initial commit --- .../reference/global_objects/date/index.html | 261 +++++++++++++++++++++ 1 file changed, 261 insertions(+) create mode 100644 files/ar/web/javascript/reference/global_objects/date/index.html (limited to 'files/ar/web/javascript/reference/global_objects/date/index.html') diff --git a/files/ar/web/javascript/reference/global_objects/date/index.html b/files/ar/web/javascript/reference/global_objects/date/index.html new file mode 100644 index 0000000000..efaa40ce31 --- /dev/null +++ b/files/ar/web/javascript/reference/global_objects/date/index.html @@ -0,0 +1,261 @@ +--- +title: Date | التاريخ +slug: Web/JavaScript/Reference/Global_Objects/Date +tags: + - Date + - JavaScript + - NeedsTranslation + - TopicStub +translation_of: Web/JavaScript/Reference/Global_Objects/Date +--- +
{{JSRef}}
+ +

Creates a JavaScript Date instance that represents a single moment in time. Date objects are based on a time value that is the number of milliseconds since 1 January, 1970 UTC.

+ +

البنيه

+ +
new Date();
+new Date(value);
+new Date(dateString);
+new Date(year, month[, day[, hour[, minutes[, seconds[, milliseconds]]]]]);
+
+ +
+

Note: JavaScript Date objects can only be instantiated by calling JavaScript Date as a constructor: calling it as a regular function (i.e. without the {{jsxref("Operators/new", "new")}} operator) will return a string rather than a Date object; unlike other JavaScript object types, JavaScript Date objects have no literal syntax.

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+ +

Parameters

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+

Note: Where Date is called as a constructor with more than one argument, if values are greater than their logical range (e.g. 13 is provided as the month value or 70 for the minute value), the adjacent value will be adjusted. E.g. new Date(2013, 13, 1) is equivalent to new Date(2014, 1, 1), both create a date for 2014-02-01 (note that the month is 0-based). Similarly for other values: new Date(2013, 2, 1, 0, 70) is equivalent to new Date(2013, 2, 1, 1, 10) which both create a date for 2013-03-01T01:10:00.

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+ +
+

Note: Where Date is called as a constructor with more than one argument, the specifed arguments represent local time. If UTC is desired, use new Date({{jsxref("Date.UTC()", "Date.UTC(...)")}}) with the same arguments.

+
+ +
+
value
+
Integer value representing the number of milliseconds since 1 January 1970 00:00:00 UTC (Unix Epoch).
+
dateString
+
String value representing a date. The string should be in a format recognized by the {{jsxref("Date.parse()")}} method (IETF-compliant RFC 2822 timestamps and also a version of ISO8601). +
+

Note: parsing of date strings with the Date constructor (and Date.parse, they are equivalent) is strongly discouraged due to browser differences and inconsistencies.

+
+
+
year
+
Integer value representing the year. Values from 0 to 99 map to the years 1900 to 1999. See the {{anch("Example:_Two_digit_years_map_to_1900_-_1999", "example below")}}.
+
month
+
Integer value representing the month, beginning with 0 for January to 11 for December.
+
day
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Optional. Integer value representing the day of the month.
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hour
+
Optional. Integer value representing the hour of the day.
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minute
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Optional. Integer value representing the minute segment of a time.
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second
+
Optional. Integer value representing the second segment of a time.
+
millisecond
+
Optional. Integer value representing the millisecond segment of a time.
+
+ +

Description

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Properties

+ +
+
{{jsxref("Date.prototype")}}
+
Allows the addition of properties to a JavaScript Date object.
+
Date.length
+
The value of Date.length is 7. This is the number of arguments handled by the constructor.
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+ +

Methods

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+
{{jsxref("Date.now()")}}
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Returns the numeric value corresponding to the current time - the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC.
+
{{jsxref("Date.parse()")}}
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Parses a string representation of a date and returns the number of milliseconds since 1 January, 1970, 00:00:00, UTC. +
+

Note: Parsing of strings with Date.parse is strongly discouraged due to browser differences and inconsistencies.

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+
+
{{jsxref("Date.UTC()")}}
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Accepts the same parameters as the longest form of the constructor (i.e. 2 to 7) and returns the number of milliseconds since 1 January, 1970, 00:00:00 UTC.
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+ +

JavaScript Date instances

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All Date instances inherit from {{jsxref("Date.prototype")}}. The prototype object of the Date constructor can be modified to affect all Date instances.

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Date.prototype Methods

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{{page('/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/prototype', 'Methods')}}
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Examples

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Several ways to create a Date object

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The following examples show several ways to create JavaScript dates:

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+

Note: parsing of date strings with the Date constructor (and Date.parse, they are equivalent) is strongly discouraged due to browser differences and inconsistencies.

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+ +
var today = new Date();
+var birthday = new Date('December 17, 1995 03:24:00');
+var birthday = new Date('1995-12-17T03:24:00');
+var birthday = new Date(1995, 11, 17);
+var birthday = new Date(1995, 11, 17, 3, 24, 0);
+
+ +

Two digit years map to 1900 - 1999

+ +

In order to create and get dates between the years 0 and 99 the {{jsxref("Date.prototype.setFullYear()")}} and {{jsxref("Date.prototype.getFullYear()")}} methods should be used.

+ +
var date = new Date(98, 1); // Sun Feb 01 1998 00:00:00 GMT+0000 (GMT)
+
+// Deprecated method, 98 maps to 1998 here as well
+date.setYear(98);           // Sun Feb 01 1998 00:00:00 GMT+0000 (GMT)
+
+date.setFullYear(98);       // Sat Feb 01 0098 00:00:00 GMT+0000 (BST)
+
+ +

Calculating elapsed time

+ +

The following examples show how to determine the elapsed time between two JavaScript dates in millisconds.

+ +

Due to the differing lengths of days (due to daylight saving changeover), months and years, expressing elapsed time in units greater than hours, minutes and seconds requires addressing a number of issues and should be thoroughly researched before being attempted.

+ +
// using Date objects
+var start = Date.now();
+
+// the event to time goes here:
+doSomethingForALongTime();
+var end = Date.now();
+var elapsed = end - start; // elapsed time in milliseconds
+
+ +
// using built-in methods
+var start = new Date();
+
+// the event to time goes here:
+doSomethingForALongTime();
+var end = new Date();
+var elapsed = end.getTime() - start.getTime(); // elapsed time in milliseconds
+
+ +
// to test a function and get back its return
+function printElapsedTime(fTest) {
+  var nStartTime = Date.now(),
+      vReturn = fTest(),
+      nEndTime = Date.now();
+
+  console.log('Elapsed time: ' + String(nEndTime - nStartTime) + ' milliseconds');
+  return vReturn;
+}
+
+yourFunctionReturn = printElapsedTime(yourFunction);
+
+ +
+

Note: In browsers that support the {{domxref("window.performance", "Web Performance API", "", 1)}}'s high-resolution time feature, {{domxref("Performance.now()")}} can provide more reliable and precise measurements of elapsed time than {{jsxref("Date.now()")}}.

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+ +

Specifications

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SpecificationStatusComment
{{SpecName('ESDraft', '#sec-date-objects', 'Date')}}{{Spec2('ESDraft')}} 
{{SpecName('ES6', '#sec-date-objects', 'Date')}}{{Spec2('ES6')}} 
{{SpecName('ES5.1', '#sec-15.9', 'Date')}}{{Spec2('ES5.1')}} 
{{SpecName('ES1')}}{{Spec2('ES1')}}Initial definition. Implemented in JavaScript 1.1.
+ +

Browser compatibility

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{{CompatibilityTable}}
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FeatureChromeFirefox (Gecko)Internet ExplorerOperaSafari
Basic support{{CompatVersionUnknown}} [1]{{CompatVersionUnknown}} [1]{{CompatVersionUnknown}} [2]{{CompatVersionUnknown}} [1]{{CompatVersionUnknown}} [1]
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FeatureAndroidChrome for AndroidFirefox Mobile (Gecko)IE MobileOpera MobileSafari Mobile
Basic support{{CompatVersionUnknown}}{{CompatVersionUnknown}}{{CompatVersionUnknown}}{{CompatVersionUnknown}}{{CompatVersionUnknown}}{{CompatVersionUnknown}}
+
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[1] Some browsers can have issues when parsing dates: 3/14/2012 blog from danvk Comparing FF/IE/Chrome on Parsing Date Strings

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[2] ISO8601 Date Format is not supported in Internet Explorer 8, and other version can have issues when parsing dates

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