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•  JavaScript Create Your Own Objects

An object is just a special kind of data, with a collection of properties and methods.

Let's illustrate with an example: A person is an object. Properties are the values associated with the object. The persons' properties include name, height, weight, age, skin tone, eye color, etc. All persons have these properties, but the values of those properties will differ from person to person. Objects also have methods. Methods are the actions that can be performed on objects. The persons' methods could be eat(), sleep(), work(), play(), etc.

Properties

The syntax for accessing a property of an object is:

objName.propName

 

There are different ways to create a new object:

1. Create a direct instance of an object

The following code creates an instance of an object and adds four properties to it:

personObj=new Object()

personObj.firstname="John"

personObj.lastname="Doe"

personObj.age=50

personObj.eyecolor="blue"

Adding a method to the personObj is also simple. The following code adds a method called eat() to the personObj:

personObj.eat=eat

2. Create a template of an object

The template defines the structure of an object:

function person(firstname,lastname,age,eyecolor)

{

this.firstname=firstname

this.lastname=lastname

this.age=age

this.eyecolor=eyecolor

}

Notice that the template is just a function. Inside the function you need to assign things to this.propertyName. The reason for all the "this" stuff in is that you're going to have more than one person at a time (which person you're dealing with must be clear). That's what "this" is: the instance of the object at hand.

Once you have the template, you can create new instances of the object, like this:

myFather=new person("John","Doe",50,"blue")

myMother=new person("Sally","Rally",48,"green")