JavaScript Tutorials - Herong's Tutorial Examples - 2.33, by Herong Yang
The "Object" Object Type - The Root Object Type
This section provides a quick description and a tutorial example script of the 'Object' built-in object type, which is the root or base object type of all other object types.
The "Object" object type is probably the most important built-in object type. It has the following main features:
Here is a tutorial sample script showing you some of those features:
// Object_Object_Type.js // Copyright (c) 2013 HerongYang.com. All Rights Reserved. // Creating an object of the "Object" object type var myObject = new Object(); // Adding properties to the object myObject.name = "Unknown"; myObject.size = "1.71m"; myObject.weight = "65kg"; // Checking the object println("About the myObject:"); println(" Type: "+(typeof myObject)); println(" Instance Of Object: "+(myObject instanceof Object)); println(" Properties:"); for (var item in myObject) { println(" "+item+": "+myObject[item]); } // Creating an object of the "Book" object type var myBook = new Book("JavaScript Tutorial", "Herong Yang"); // Checking the object println("About the myBook:"); println(" Type: "+(typeof myBook)); println(" Instance Of Object: "+(myBook instanceof Object)); println(" Instance Of Book: "+(myBook instanceof Book)); println(" Properties:"); for (var item in myBook) { println(" "+item+": "+myBook[item]); } // Defining the constructor for a new object type function Book(title, author) { this.title = title; this.author = author; }
If you run this script with "jrunscript", you will get:
About the myObject: Type: object Instance Of Object: true Properties: weight: 65kg name: Unknown size: 1.71m About the myBook: Type: object Instance Of Object: true Instance Of Book: true Properties: title: JavaScript Tutorial author: Herong Yang
"myBook" is an instance of "Book" and "Object", because "Book" is sub type of "Object" by default.
Read other "Object" related chapters to see more tutorial examples.
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
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
Overview of Built-in Object Types
►The "Object" Object Type - The Root Object Type
The "Global" Object Type - The Invisible Global Container
Global Properties and Functions Defined in ECMAScript
Global Properties and Functions Provided by "jrunscript"
The "Function" Object Type - Functions Are Objects
The "Array" Object Type - Arrays Are Objects
The "JSON" Object Type - parse() and stringify()
The "String" Object Type - Not Equal to String Primitive Type
The "Boolean" Object Type - Wrapping Boolean Values into Objects
The "Number" Object Type - Not Equal to Number Primitive Type
The "Date" Object Type - Managing Dates and Times
The "RegExp" Object Type - Regular Expression Patterns
The "Error" Object Type - Runtime Exceptions
The "Math" Object Type - The Math Container
W3C's Document Object Model (DOM) Specifications