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Introduction
An object is something that has properties and methods. For example, a car has properties like color, model, and methods such as start, accelerate and stop.
An object in JavaScript also has properties and methods. A JavaScript object actually comprises variables and functions. A variable inside an object is called a property and a function inside an object is called a method.
Creating an Object
There are two ways to create a JavaScript object, namely using literal notation and using object constructor notation
1. Using Literal Notation
The syntax to create an object is
var objectName={
property1="=value1,
property2="=value2,
..................
.................
proeprtyn=valuen,
MyMethod: MyFunction(){ }
};
Example 1.1
<!DOCTYPE html>
<html>
<body>
<p>The Phone Object.</p>
<h3>Model:<b id="model"></b></h3>
<h3> Brand:<b id="brand"></b></h3>
<h3>Price:<b id="price"></b></h3>
<script>
var phone= {model:"Note8", brand:"Samsung", color:"white",price:"$2000"};
document.getElementById("model").innerHTML = phone.model;
document.getElementById("brand").innerHTML = phone.brand;
document.getElementById("price").innerHTML = phone.price;
</script>
</body>
</html>
The output
The Phone Object.
Model:
Brand:
Price:
The following example comprises a function:
Example 1.2
var student={
name:'George',
height:1.78,
weight:75,
bmi: function(){
var x=this.weight/Math.pow(this.height,2);
var y=x.toFixed(2);
return y;
}
};
var student_Name=document.getElementById('studentname');
student_Name.textContent=student.name;
var student_bmi=document.getElementById('bmi_index');
student_bmi.textContent=student.bmi();
The object is student that comprise properties name, height, and weight. Its method is bmi that calculates the bmi index of a particular student. Notice that each property comprises name:value pairs and must be separated by a comma.
The output
Student Name:
BMI :
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