[Demo] Add Days to a Date in JavaScript

[Demo] Add Days to a Date in JavaScript

by steven keezer

HTML

<script src="//code.jquery.com/ui/1.10.4/jquery-ui.js"></script>
<link rel="stylesheet" href="//code.jquery.com/ui/1.10.4/themes/smoothness/jquery-ui.css">
<h2>Calculate due date from point of conception:</h2>

<p>Date:
  <input id="txtDate" type="text" />
</p>
<p>
  <input type="button" onclick="getdate()" value="Calculate Conception" />
</p>
<p>Conception Date:
  <input id="Conception_Date" type="text" />
</p>

JavaScript

$(document).ready(function () {
    $('#txtDate').datepicker();
    $('#follow_Date').datepicker();
});

function getdate() {
    var tt = document.getElementById('txtDate').value;

    var date = new Date(tt);
    var newdate = new Date(date);

    newdate.setDate(newdate.getDate() + 700);
    
    var dd = newdate.getDate();
    var mm = newdate.getMonth() + 1;
    var y = newdate.getFullYear();

    var someFormattedDate = mm + '/' + dd + '/' + y;
    document.getElementById('Conception_Date').value = someFormattedDate;
}