Date automatically calculates time

A convenient method for date arithmetic. This method does not change the date instance itself, but instead returns a ...

A convenient method for date arithmetic. Instead of changing the date instance itself, this method returns a new instance of the date object created with the result of the operation. For example:

Basic usage:

var dt = new Date (' 10/29/2006 '). Add (Date.day, 5);
document.write (DT); Return ' Fri Oct 2006 00:00:00 '

//negative number will be subtracted from the value:
var dt2 = new Date (' 10/1/2006 '). Add (Date.day,-5);
document.write (DT2); Return ' Tue Sep 2006 00:00:00 '

//You can even call this method several times in a row
var dt3 = new Date (' 10/1/2006 '). Add (Date.day, 5). Add (Date.hour, 8). Add (Date.minute, -30);
document.write (DT3); Back to ' Fri Oct 06 2006 07:30:00 '