JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://jquery-ui.googlecode.com/svn/tags/latest/ui/i18n/jquery.ui.datepicker-pt-BR.js"></script>
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.9.0/themes/ui-lightness/jquery-ui.css">

    <input class="datefield2" name="date" type="text" id="date">

JavaScript

//if i put value pt-BR ,its showing as brazilian culure but when i change //its value ,it goes to else condition but do not show default culture //ie.en-US

$(function() {
        var currentCulture="pt-BR";
       // $(".datefield2").datepicker($.datepicker.regional['pt-BR']);
       if ($("#currentCulture").val() == "pt-BR") {
            $(".datefield2").datepicker({
                changeMonth: true,
                changeYear: true
            }).attr('readonly', 'readonly');
alert('qq1');
            $(".datefield2").datepicker($.datepicker.regional["pt-BR"]);
        }
        else {
            alert('qq');
            $(".datefield2").datepicker({
                changeMonth: true,
                changeYear: true,
                dateFormat: 'mm/dd/yy'
            }).attr('readonly', 'readonly');
            $(".datefield2").datepicker($.datepicker.regional[""]);
        }
    });