The "Date" Object Type - Managing Dates and Times

JavaScript Tutorials - Herong's Tutorial Examples

∟The "Date" Object Type - Managing Dates and Times

This section provides a quick description and a tutorial example script on the 'Date' built-in object type, which is used to create 'Date' objects.

The "Date" object type is a built-in object type to be used to create a "Date" object, representing a moment in time. It has the following main features:

New "Date" objects can be created with the "Date()" constructor. Note that "Date()" is also a regular function, which returns a string representation of a date.
All "Date objects have several inherited methods: toString(), valueOf(), setDate(), getDate(), etc..
The "Date" constructor offers its own methods: Date.parse(), Date.UTC(), etc..

Here is a tutorial example script showing some of those features:

// Date_Object_Type.js
// Copyright (c) 2013 HerongYang.com. All Rights Reserved.

   // Creating a new Date object
   var myObject = new Date(2008, 0, 1, 2, 3, 4);

   // Checking this object
   println("\nAbout this \"myObject\":");
   println("   Type = "+(typeof myObject));
   println("   Instance Of Object: "+(myObject instanceof Object));
   println("   Instance Of Date: "+(myObject instanceof Date));

   // Using Number's inherited methods
   var v = myObject.valueOf();
   var s = myObject.toString();
   var h = myObject.getHours();

   println("\nExecution result:");
   println("   typeof myObject = "+(typeof myObject));
   println("   typeof myObject.valueOf() = "+(typeof v));
   println("   typeof myObject.toString() = "+(typeof s));
   println("   typeof myObject.getHours(() = "+(typeof h));
   println("   value of myObject.valueOf() = "+v);
   println("   value of myObject.toString() = "+s);
   println("   value of myObject.toString() = "+h);

   println("\nUsing methods of the Date constructor:");
   var myTime = Date.parse("Tue Jan 01 2008");
   var myDate = new Date(myTime);
   println("   typeof myTime = "+(typeof myTime));
   println("   typeof myDate = "+(typeof myDate));
   println("   myTime = "+myTime);
   println("   myDate.toString() = "+myDate.toString());

If you run this script with "jrunscript", you will get:

About this "myObject":
   Type = object
   Instance Of Object: true
   Instance Of Date: true

Execution result:
   typeof myObject = object
   typeof myObject.valueOf() = number
   typeof myObject.toString() = string
   typeof myObject.getHours(() = number
   value of myObject.valueOf() = 1199170984000
   value of myObject.toString() = Tue Jan 01 2008 02:03:04 GMT-0000 
   value of myObject.toString() = 2

Using methods of the Date constructor:
   typeof myTime = number
   typeof myDate = object
   myTime = 1199163600000
   myDate.toString() = Tue Jan 01 2008 00:00:00 GMT-0000