JavaScript Adding days in milliseconds to Date object

Given a date, the task is to add days in milliseconds to it using JavaScript. To add days in milliseconds to date objects in JavaScript, some methods are used which are listed below:
JavaScript getMilliseconds() Method: This method returns the milliseconds (from 0 to 999) of the provided date and time.
Syntax:
Date.getMilliseconds()
Parameters: This method does not accept any parameters.
Return value: It returns a number, from 0 to 009, representing the milliseconds.
JavaScript setMilliseconds() Method: This method sets the milliseconds of a date object.
Syntax:
Date.setMilliseconds(millisec)
Parameters:
- millisec: This parameter is required. It specifies the number of milliseconds to be added/subtracted, midnight January 1, 1970
Return Value: It returns the new i.e updated millisecond which is set by the setMilliseconds() method.
JavaScript getTime() Method: This method returns the number of milliseconds between midnight of January 1, 1970, and the specified date.
Syntax:
Date.getTime()
Parameters: This method does not accept any parameters.
Return value: It returns a number, representing the number of milliseconds since midnight January 1, 1970.
JavaScript setTime() Method: This method sets the date and time by adding/subtracting a defines number of milliseconds to/from midnight January 1, 1970.
Syntax:
Date.setTime(millisec)
Parameters:
- millisec: This parameter is required. It specifies the number of milliseconds to be added/subtracted, midnight January 1, 1970
Return value: It returns the number of milliseconds between the date object since midnight January 1 1970.
Example 1: This example added 1 day in milliseconds to the variable today by using setTime() and getTime() methods.
Javascript
| let today = newDate();console.log("Date = "+ today);Date.prototype.addMillisecs = function(d) {    this.setTime(this.getTime() + (d));    returnthis;}let a = newDate();let d = 1;a.addMillisecs(d * 24 * 60 * 60 * 1000);console.log(a); | 
Output
Date = Tue Jun 13 2023 20:33:11 GMT+0530 (India Standard Time) Date Wed Jun 14 2023 20:33:11 GMT+0530 (India Standard Time)
Example 2: This example added 5 days in milliseconds to the variable today by using setMilliseconds() and getMilliseconds() methods.
Javascript
| let today = newDate();console.log("Date = "+ today);Date.prototype.addMillisecs= function(s) {    this.setMilliseconds(this.getMilliseconds()+s);    returnthis;}let a = newDate();let d = 5;a.addMillisecs(d * 24 * 60 * 60 * 1000);console.log(a); | 
Output
Date = Tue Jun 13 2023 20:35:02 GMT+0530 (India Standard Time) Date Sun Jun 18 2023 20:35:02 GMT+0530 (India Standard Time)
 
				 
					


