JavaScript Objects

Java Script Variables are containers for data values. Objects are variables too, but they can contain any values. think of an object as a list of values that are written as name: value pairs, with the names and the values separated by colons.

var person = {

name: “Billo”,

favcolor: “green”,

height:160,

age:35

};

Note: JavaScript objects are containers for named values. this example demonstrates how to access the age of our person object

Var person = {

name:”Gunnu”,

favcolor: “green”,

height:172,

age:30

};

var b = person.age

var g = person[“age”];

Output:3030

JavaScript built-in length property is used to can not the number of characters in a property or string

var course = {name: “Js”, lessons: 41};

document.write (course.name.length);

Output:

Note: Object are one of the core concept in JavaScript

Object Methods: An object method is a property that contains a function definition.

Use the following syntax to access an object method.

objectName.methodName()

As you already know, document.write() outputs data.

The write() function is actually a method of the document object.

Note: Methods are functions that are stored as an object property

Object Constructor:

function person(name,age,color){

this.name = name;

this.age =age;

this.favcolor = color;

}

This keyword refers to the current object.

Note: this is not verable. it is a keyword, and its value cannot be chased

Creating Object:

Once you have an object constructor, you can use the new keyword to create new objects of the same type.

Var b = new person(“billo”,35,”green”);

Var g = new person (“gunnu”,30, “Black”);

document.write(b.age);

document.write(g.name);

Output: 35 gunnu

Note: b,g are now object of person type. their properties are assigned to the corresponding values.

Creating Objects:

function person(name,age){

this.name = name;

this.age = age;

}

var Billo = new person(“billo”,35);

var Gunnu = new person(“gunnu”,30);

document.write(Billo.age);

Output: 35

Access the properties of the object by using the dot syntax as we did before.

Object Name	Property’s Name
Billo	name,age
Gunnu	name, age

Object Initialization:

Use the object literal or initializer syntax to create single objects.

var Billo = {name: “billo”,age:35};

var Gunnu = {name: “gunnu”,age:30};

Note: object properties can either contain primitive data types or another object

Object Initialization:

var Billo = {

name: “billo”;

age: 35

};

var Gunnu = {

name: “gunnu”;

age= 30

};

document.write(Billo.age);

Output: 35

Note: don’t forget about the second accessing syntax Billo[‘age’]