JavaScript Tutorials - Herong's Tutorial Examples - 2.33, by Herong Yang
Objects of "Object" Data Type
This section provides a quick description of the 'Object' data type, its properties and methods. A tutorial example is provided on how to create and test an object of the 'Object' data type.
To learn how to use objects in JavaScript, we need to start with the "Object" data type, which has the following basic features:
Here is tutorial example showing some of those properties and methods defined on "Object" data type:
<html> <!-- Object_Object.html Copyright (c) 2008 HerongYang.com. All Rights Reserved. --> <head> <title>Objects of "Object"</title> </head> <body> <pre> <script type="text/javascript"> // Creating an object and assigning it to a variable var mySite = new Object(); // Showing the built-in properties document.writeln('mySite.constructor: '+mySite.constructor); document.writeln('mySite.prototype: '+mySite.prototype); // Adding a property this object only mySite.name = "herongyang.com"; // Converting this object to a string document.writeln('mySite.toString(): '+mySite.toString()); // Converting this object to a numeric value document.writeln('mySite.valueOf(): '+mySite.valueOf()); // Testing a property of this object document.writeln('mySite.hasOwnProperty("name"): ' +mySite.hasOwnProperty("name")); document.writeln('mySite.hasOwnProperty("constructor"): ' +mySite.hasOwnProperty("constructor")); document.writeln('mySite.hasOwnProperty("address"): ' +mySite.hasOwnProperty("address")); </script> </pre> </body> </html>
Run this example, you will get this interesting result:
mySite.constructor: function Object() { [native code] } mySite.prototype: undefined mySite.toString(): [object Object] mySite.valueOf(): [object Object] mySite.hasOwnProperty("name"): true mySite.hasOwnProperty("constructor"): false mySite.hasOwnProperty("address"): false
Explanation of this result will be provided in next sections.
Table of Contents
ECMAScript Language Specification and JavaScript Dialects
Data Types, Variables and Expressions
Creating, Accessing, and Manipulating Arrays
Defining and Calling Functions
Web Browser Supporting JavaScript
Server-Side and Client-Side Web Scripting
►Objects of "Object" Data Type
Adding and Deleting Object Own Properties
Adding and Deleting Object Own Methods
Using "this" Keyword to Represent Current Object
Object Literals of the "Object" Type
Objects with Indexed Properties
Differences between "Object" and "Array"
Using "Array" Objects as "Object" Objects
Defining Your Own Object Types
Inheritance of Properties and Methods through the Prototype Object Chain
'jrunscript' - JavaScript Shell Command from JDK
Using Functions as "Function" Objects
Introduction to Built-in Object Types
W3C's Document Object Model (DOM) Specifications