Once a Date object is created, a number of methods allow you to
operate on it. Most methods simply allow you to get and set the year, month,
day, hour, minute, second, and millisecond fields of the object, using either
local time or UTC (universal, or GMT) time.
The ECMAScript standard requires the Date object to be able to
represent any date and time, to millisecond precision, within 100 million days
before or after 1/1/1970. This is a range of plus or minus 273,785 years, so
the JavaScript is able to represent date and time till year 275755.
Syntax:
Here are different variant of Date() constructor:
|
new Date( )
new Date(milliseconds)
new Date(datestring)
new
Date(year,month,date[,hour,minute,second,millisecond ])
|
Note: Paramters
in the brackets are always optional
Here is the description of the parameters:
- No Argument: With no
arguments, the Date( ) constructor creates a Date object set to the
current date and time.
- milliseconds: When one numeric
argument is passed, it is taken as the internal numeric representation of
the date in milliseconds, as returned by the getTime( ) method. For
example, passing the argument 5000 creates a date that represents five
seconds past midnight on 1/1/70.
- datestring:When one string
argument is passed, it is a string representation of a date, in the format
accepted by the Date.parse( ) method.
- 7 agruments: To use the last
form of constructor given above, Here is the description of each argument:
1. year: Integer value representing the year. For compatibility (in order
to avoid the Y2K problem), you should always specify the year in full; use
1998, rather than 98.
2. month: Integer value representing the month, beginning with 0 for January
to 11 for December.
3. date: Integer value representing the day of the month.
4. hour: Integer value representing the hour of the day (24-hour scale).
5. minute: Integer value representing the minute segment of a time reading.
6. second: Integer value representing the second segment of a time reading.
7. millisecond: Integer value representing the millisecond segment of a time
reading.
Date Properties:
Here is a list of each property and their description.
|
Property
|
Description
|
|
|
Specifies the function that creates an object's prototype.
|
|
|
The prototype property allows you to add properties and methods
to an object.
|
Date Methods:
a) getDate() :- Returns present Date.
Ex : var d=new Date();
d.getDate();
b) getDay() :- Returns week day.
Ex : d.getDay();
c) getMonth() :- Returns month.
Ex : d.getMonth();
d) getFullYear() :- Returns year.
Ex : d.getFullYear();
e) getTime() :- Returns Time.
Ex : d.getTime();
f) getHours() :- Returns time in hours.
Ex : d.getHours();
g) getMinutes() :- Returns time in minutes.
Ex : d.getMinutes();
h) getSeconds() :- Returns time in seconds.
Ex : d.getSeconds();
get() To get date and time.
set() To set date and time.
Ex : d.setDate();
Date Static Methods:
In addition to the many instance methods listed previously, the
Date object also defines two static methods. These methods are invoked through
the Date( ) constructor itself:
|
Method
|
Description
|
|
|
Parses a string representation of a date and time and returns
the internal millisecond representation of that date.
|
|
|
Returns the millisecond representation of the specified UTC date
and time.
|
How to use the Date() method
to get today's date.
getTime()
getTime() returns the number of milliseconds since 01.01.1970.
toUTCString()
How to use toUTCString() to convert today's date (according to UTC) to a
string.
getDay()
Use getDay() and an array to write a weekday, and not just a number.
5. Date Object
Manipulates Date and Time.
Methods
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>
<body>
<script>
var date=new Date();
document.write("Date :"+date+"<br/>");
document.write("Day: "+date.getDate()+"<br/>");
document.write("Month :"+date.getMonth()+"<br/>");
document.write("Year :"+date.getYear()+"<br/>");
document.write("Hours :"+date.getHours()+"<br/>");
document.write("Minutes :"+date.getMinutes()+"<br/>");
document.write("Seconds :"+date.getSeconds()+"<br/>");
</script>
</body>
</html>
Ex2: digital clock
<!DOCTYPE html>
<html>
<head>
<script>
function startTime()
{
var today=new Date();
var h=today.getHours();
var m=today.getMinutes();
var s=today.getSeconds();
// add a zero in front of numbers<10
m=checkTime(m);
s=checkTime(s);
document.getElementById('txt').innerHTML=h+":"+m+":"+s;
t=setTimeout(function(){startTime()},500);
}
function checkTime(i)
{
if (i<10)
{
i="0" + i;
}
return i;
}
</script>
</head>
<body onload="startTime()">
<div id="txt"></div>
</body>
</html>
