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Control Statements
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Function & Events
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Array and its Types
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OOP : Object Oriented Programming
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Javascript Standards
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Javascript : Advanced 1
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Javascript : Advanced 2
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Additional JavaScript
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In the Previous Sections, you have learned after declaring constructor, new properties and methods cannot be added again.

To Overcome This Issue, Prototypes are Introduced.

All Javascript Objects inherit Properties and Methods from Prototypes.

So, You can now add properties and methods to Constructor By using Prototypes.


To Declare New Property:

function constructorName(){ // constructorVariables } constructorName.prototype.newProperty = newValue;

To Declare New Method:

function constructorName(){ // constructorVariables } constructorName.prototype.methodName= function(){ //Statements }


function home(homeName,homeSize,homeColour){ = homeName; this.size = homeSize; this.colour = homeColour; } home.prototype.noOfRooms = 6; // Declaring Property home.prototype.getDetails = function(){ // Declaring Method return "Hello!!! Welcome to " + + " Home, it is "+ this.size + " large and has " + this.noOfRooms + " Rooms of "+ this.colour + " Colour."; } var ramHome = new home("Ram's", "500 sq. ft.","blue"); console.log(ramHome.getDetails()); // Output // Hello!!! Welcome to Ram's Home, it is 500 sq. ft. large and has 6 Rooms of blue Colour.


We have declared property noOfRooms and method getDetails

Do You Know???

You can change the Methods and Properties or Pre-Defined Objects like Date, Array


  1. Date objects inherit properties and methods from Date.prototype
  2. Array objects inherit properties and methods from Array.prototype

So, If you change the Array.prototype you can actually Change the Standard JS Objects.

Only modify your own prototypes. Never modify the prototypes of Standard JavaScript objects.

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