JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <div id="error" style="display: none;">Bad date</div>
    <input id="first" type="text" value="" /> 
    <input id="hello" type="text" value="234.12.1984" />
    <button type="submit">Submit</button>
</form>

JavaScript

$("#hello").datepicker();

$("#first").focus();

$('form').submit(function(event){
    try{
        var d = $('#hello');
        $.datepicker.parseDate(d.datepicker( "option", "dateFormat" ), d.val());
    }catch(e){
        event.preventDefault();
        $('#error').show();
        return false;
    }
});