Question: I have one text box. When I enter a date with the format `MM/DD/YYYY` in that textbox and click outside the textbox I need to display the result as `MM/DD/YYYY+3` using JavaScript.

For example, if my date is 12/31/2013 then the result would be 01/03/2014.

Answer: 
Hope this link will help you to find the answer: 

[adding-number-of-days-to-an-entered-date-in-javascript](http://www.codeigniter.in/blog/post/adding-number-of-days-to-an-entered-date-in-javascript).
Have a look at the excellent library [moment.js](http://momentjs.com/) with which you easily can add three days to your original date.

In your case it would be something like:

```
var input = moment(myTextBoxValue);
input.add('d', 3); // input is now 3 days later

```