JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-2.1.4.min.js"></script>
<input type="date" id="date-input" required />
<button id="submit">Submit</button>

JavaScript

var day, month, year;

$('#submit').on('click', function(){
  day = $('#date-input').getDate();
  month = $('#date-input').getMonth() + 1;
  year = $('#date-input').getFullYear();
  alert(day, month, year);
});