Javascript - Date prototype Property

The prototype constructor allows you to add new properties and methods to the Date() class.

Description

The prototype constructor allows you to add new properties and methods to the Date() class.

Syntax

Date.prototype.name = value

Example

The following code creates a new date method that gives the date object a month-name property called myProp:

Demo

//call the new myMet() method, and display this month's name, using the new myProp property.
Date.prototype.myMet = function() {
    if (this.getMonth() == 0){this.myProp = "January"};
    if (this.getMonth() == 1){this.myProp = "February"};
    if (this.getMonth() == 2){this.myProp = "March"};
    if (this.getMonth() == 3){this.myProp = "April"};
    if (this.getMonth() == 4){this.myProp = "May"};
    if (this.getMonth() == 5){this.myProp = "June"};
    if (this.getMonth() == 6){this.myProp = "July"};
    if (this.getMonth() == 7){this.myProp = "August"};
    if (this.getMonth() == 8){this.myProp = "September"};
    if (this.getMonth() == 9){this.myProp = "October"};
    if (this.getMonth() == 10){this.myProp = "November"};
    if (this.getMonth() == 11){this.myProp = "December"};
};


var d = new Date();
d.myMet();/*from   ww w  . j  a v  a 2s  . co  m*/
console.log(d.myProp);

Result