JavaScript Tutorials - Herong's Tutorial Examples - Version 2.21, by Dr. Herong Yang

JavaScript Tutorials - Herong's Tutorial Examples

∟Inheritance of Properties and Methods through the Prototype Object Chain

∟Prototype Object Chain Summary

Here is a summary of how object, constructor, and prototype are related to each other.

• JavaScript supports objects without class.
• An object is created from a constructor function, which is also an object.
• A property can be added to an object through the constructor during the object creation process.
• A property can be added to an object after it has been created.
• A constructor contains a property called "prototype", which points to an object serving as the prototype to the constructor.
• An object inherits all properties of its constructor's prototype.
• The inheritance process is recursive process, which allows an object to inherit from multiple levels of prototypes of its constructor prototype chain.
• The prototype of the constructor "Object" is base prototype of any prototype chain.
• Methods follow same inheritance rules as properties. Actually, methods are properties with function definitions as their values.
• The base prototype has several built-in default properties and methods.

Here is my diagram representing relations of object, constructor, and prototype. It also shows how object properties and methods are inherited from its parent prototypes:

Table of Contents

 About This Book

 Introduction to JavaScript

 ECMAScript Language Specification and JavaScript Dialects

 Data Types, Variables and Expressions

 Flow Control Statements

 Creating, Accessing, and Manipulating Arrays

 Defining and Calling Functions

 Web Browser Supporting JavaScript

 Server-Side and Client-Side Web Scripting

 Introduction to Objects

 Defining Your Own Object Types

►Inheritance of Properties and Methods through the Prototype Object Chain

 Inheriting from Constructor's Prototype Object

 Changing the Constructor's Prototype Object

 Inheriting Properties from Two Level Prototype Objects

 Built-in Properties and Methods in "Object.prototype"

 Using "hasOwnProperty()" Method to Test Inherited Properties

 Setting the "constructor" Property in the "prototype" Object

 Adding Local Methods at the Object Level

 Adding Inherited Methods at the Prototype Level

 Building Multiple Levels of Prototype Objects

►Prototype Object Chain Summary

 'jrunscript' - JavaScript Shell Command from JDK

 Using Functions as "Function" Objects

 Introduction to Built-in Object Types

 W3C's Document Object Model (DOM) Specifications

 References

 PDF Printing Version

Prototype Object Chain Summary - Updated in 2013, by Dr. Herong Yang