JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.16/themes/base/jquery-ui.css" type="text/css" media="all" />
<input type="text" id="ctl00_CPH_K1ZoneContenu1_Cadr_Section01_Cadriciel_FS_Section01_K1ChampDate1__cs" />

JavaScript

$(function() {
    function ctl00_CPH_K1ZoneContenu1_Cadr_Section01_Cadriciel_FS_Section01_K1ChampDate1__cs_beforeShow(input, inst) {
        inst.dpDiv.css({ marginLeft: input.offsetWidth + 'px' }); 
    }
    function ctl00_CPH_K1ZoneContenu1_Cadr_Section01_Cadriciel_FS_Section01_beforeShowDay(d) {
        var dateState, hasEnabledDates, hasDisabledDates, dayToVerify, disabledDates, disabledDatesDescr, enabledDates, enabledDatesDescr, disabledDayPos, enabledDayPos;
        dateState = null; 
        dayToVerify = d.getFullYear() + "-" + d.getMonth() + "-" + d.getDate(); 
        enabledDates = new Array(); 
        enabledDatesDescr = new Array(); 
        disabledDates = new Array("2011-8-28"); 
        disabledDatesDescr = new Array("Today's date is disabled using the beforeShowDay event."); 
        hasEnabledDates = (enabledDates.length > 0) ? true : false; 
        hasDisabledDates = (disabledDates.length > 0) ? true : false; 
        enabledDayPos = $.inArray(dayToVerify, enabledDates); 
        disabledDayPos = $.inArray(dayToVerify, disabledDates); 
        if ((hasEnabledDates && enabledDayPos === -1) || (hasDisabledDates && disabledDayPos !== -1)) {
            if (hasEnabledDates && enabledDayPos === -1) {
                dateState = [false, "", ""]; 
            }
            if (hasDisabledDates && disabledDayPos !== -1) {
                dateState = [false, "", disabledDatesDescr[disabledDayPos]]; 
            }
        }
        else if ((hasDisabledDates && disabledDayPos === -1) || (hasEnabledDates && enabledDayPos !== -1)) {
            if (hasDisabledDates && disabledDayPos === -1) {
                dateState = [true, "", ""]; 
            }
            if (hasEnabledDates && enabledDayPos !== -1) {
                dateState = [true, "", enabledDatesDescr[enabledDayPos]]; 
            }
        }
        return dateState;
    }
    $("#ctl00_CPH_K1ZoneContenu1_Cadr_Section01_Cadriciel_FS_Section01_K1ChampDate1__cs").datepicker({
       ...