JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/smoothness/jquery-ui.css">
<input class="datepicker" />

JavaScript

$('.datepicker').datepicker().bind('click keyup', function() {
    if ($('#ui-datepicker-div :last-child').is('table'))
        $('#ui-datepicker-div').prepend('<p>hello world</p>');
});