JSFiddle - React, Tailwind, and code Playground

HTML

<p>Date:
  <input type="text" id="datepicker" />
</p>
<p>Stuff:
  <input type="text" id="special" />
</p>

JavaScript

var datavalues = {
  "03/07/2016": "38",
  "03/12/2016": "39"
};
$(function() {
  var $result = $("#special");
  $('#datepicker').datepicker({
    inline: true,
    onSelect: function(dt, obj) {
      $result.val(datavalues[dt]);
    },
    altField: "#result"
  });
});