JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://campus.vividconcept.com/assets/js/jquery-ui.multidatespicker.js"></script>
<link rel="stylesheet" href="http://campus.vividconcept.com/assets/css/my_jquery-ui.css">
<link rel="stylesheet" href="http://campus.vividconcept.com/assets/jquery-ui-1.9.1.custom/css/humanity/jquery-ui-1.9.1.custom.css">
<input type="button" value="RĂ©percuter" class="button" id="btnRepercute" />
<div id = "dateMultiCalendar_1"></div>

JavaScript

$('#dateMultiCalendar_1').multiDatesPicker({
           // $.datepicker.regional[ "fr" ]
           //beforeShowDay: $.datepicker.noWeekends
    beforeShowDay: function (date) {
        if (date.getDay() >= 1 && date.getDay() <= 5)
            return [true, ''];
        else
            return [false, ''];
     }
});

$('#btnRepercute').click(function(){
    $('#dateMultiCalendar_1').toggle('show');
});