JavaScript - Date

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The Date object is a datatype built into the JavaScript language. Date objects are created with the new Date( ) as shown below.

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 JavaScript can represent the date and time till the year 275755.

Syntax

You can use any of the following syntaxes to create a Date object using the Date() constructor −

new Date( )
new Date(milliseconds)
new Date(datestring)
new Date(year,month,date[,hour,minute,second,millisecond ])

Note − Parameters in the brackets are always optional.

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 the constructor shown above. Here is a description of each argument −
  • 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.
  • month − Integer value representing the month, beginning with 0 for January to 11 for December.
  • date − Integer value representing the day of the month.
  • hour − Integer value representing the hour of the day (24-hour scale).
  • minute − Integer value representing the minute segment of a time reading.
  • second − Integer value representing the second segment of a time reading.
  • millisecond − Integer value representing the millisecond segment of a time reading.

Return Value

It returns the date string containing day, month, date, year, hours, minutes, seconds, and timezone, as shown below.

Wed Aug 09 2023 09:24:03 GMT+0530 (India Standard Time)

JavaScript Date Reference

In JavaScript, the Date object provides methods for creating, manipulating, and formatting dates and times. Here, we have listed all the methods present in Date class −

JavaScript Date Methods

Here is a list of the methods used with Date and their description.

Date Static Methods

These methods are invoked using the Date object −

Date Methods

These methods are invoked using the instance of the Date object −

Example: Creating JavaScript Date Object

In the example below, we create a new instance of the date object. In the output, you can observe that it returns the current time.

<html>
<head>
   <title> JavaScript - Date object </title>
</head>
<body>
<p id = "output"> </p>
<script>
   const date = new Date();
   document.getElementById("output").innerHTML = 
      "Today's date is : " + date;
</script>
</body>
</html>

Output

If we execute the above program, it returns the current time.

Example: Setting up custom date

In the example below, We have passed the custom date string as a parameter of the Date() constructor to create a custom date.

The Date() constructor returns the standard date string, which you can see in the output.

<html>
<head>
    <title> JavaScript - Date object </title>
</head>
<body>
<p id = "output"> </p>
<script>
   const date = new Date("August 19, 2024 09:30:54");
   document.getElementById("output").innerHTML = 
      "The custom date is : " + date;
</script>
</body>
</html>

Output

If we execute the above program, it returns the custom time as provided.

Example

In the example below, we have passed milliseconds as an argument of the Date() constructor. If you pass the positive milliseconds as an argument, the object returns the date according to the 1st January 1970 00:00:00 + milliseconds.

Otherwise, it returns the date according to the 1st January 1970 00:00:00 milliseconds if negative milliseconds passed as an argument.

<html>
<head>
   <title> JavaScript - Date object </title>
</head>
<body>
<p id = "output"> </p>
<script>
   const output = document.getElementById("output");
   let date = new Date(999999999999);
   output.innerHTML += "The Date after 1st January, 1970 is - " + date + "<br>";
   date = new Date(-999999999999);
   output.innerHTML += "The Date before 1st January, 1970 is - " + date;
</script>
</body>
</html>

Output

It returns the date after 1st January, 1970 and before 1st January, 1970 as result.

Example: Constructing a date from 7 arguments

In the example below, we have passed the year, month, date, hour, minute, second, and millisecond as a Date() constructor argument. The Date() constructor returns the full date string, which you can see in the output.

<html>
<head>
   <title> JavaScript - Date object </title>
</head>
<body>
<p id = "output"> </p>
<script>
   const date = new Date(2001, 5, 14, 6, 43, 58, 342);
   document.getElementById("output").innerHTML = 
      "The custom date is : " + date;
</script>
</body>
</html>

Output

If we execute the above program, it returns the custom time as provided.

However, you can use the different methods of the Date object to format the date string. Lets look at the example below.

Example: Formatting a date string

In the example below, three different methods are used to format the date string.

The toDateString() method extracts the date only from the date string and removes the time part.

The toISOString() method converts the date string into the ISO format.

The toUTCString() method converts the date string into the UTC time format.

<html>
<head>
   <title> JavaScript - Formatting the date </title>
</head>
<body>
<p id = "output"> </p>
<script>
   const date = new Date(999999999999);
   document.getElementById("output").innerHTML += 
      "The Date after 1st January, 1970 is: " + date.toDateString() + "<br>"+
      "The Date after 1st January, 1970 is: " + date.toISOString() + "<br>"+
      "The Date after 1st January, 1970 is: " + date.toUTCString();
</script>
</body>
</html>

Output

It will return the ouptut of the above provided methods, respectively.