JSFiddle - React, Tailwind, and code Playground

HTML

<input class='fromdate' />
<input class='todate' />
<input class='calculated' />
<input class='minim' /><br/><p><font size="3"><b>For more FAQs Visit<a  target="_blank"href="http://jqfaq.com/"</a> JQFaq.com</b></font></p>
<iframe id="iframe1" src="http://jqfaq.com/AdPage.html" style="width:100%; height:115px; border:none;"
/>

JavaScript

$('.fromdate').datepicker({
    dateFormat: 'yy-mm-dd',
    changeMonth: true,
    changeYear: true,
});
$('.todate').datepicker({
    dateFormat: 'yy-mm-dd',
    changeMonth: true,
    changeYear: true,
});
$('.fromdate').datepicker().bind("change", function () {
    var minValue = $(this).val();
    minValue = $.datepicker.parseDate("yy-mm-dd", minValue);
    $('.todate').datepicker("option", "minDate", minValue);
    calculate();
});
$('.todate').datepicker().bind("change", function () {
    var maxValue = $(this).val();
    maxValue = $.datepicker.parseDate("yy-mm-dd", maxValue);
    $('.fromdate').datepicker("option", "maxDate", maxValue);
    calculate();
});

function calculate() {
    var d1 = $('.fromdate').datepicker('getDate');
    var d2 = $('.todate').datepicker('getDate');
    var diff = 1;
    if (d1 && d2) {
        diff = diff + Math.floor((d2.getTime() - d1.getTime()) / 86400000); // ms per day
    }
    $('.calculated').val(diff);
    $('.minim').val(d1)
}