JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/cupertino/jquery-ui.css">
<form>
    <input type="text" name="firstname" id="firstname" value="John" ><br/>
    <input type="text" name="lastname" id="lastname" value="Smith" ><br/>
    <input type="text" name="email" id="email" value="[email protected]" ><br/>
    <!--input type="text" name ="date" id="datepicker" /><br/-->
    <div id="datepicker"></div>
    <input type="hidden" name="date" id="date"><br/>
    <button type="submit" id="submit" >
      Submit
    </button>
</form>

<div id="output"></div>

JavaScript

$(function() {
    $("#datepicker").datepicker({altField: '#date'});

    $('#submit').click(function() {
        $('#output').html($('form').serialize());
    });
});