JSFiddle - React, Tailwind, and code Playground

HTML

<input id="in1" value="what">
<button id="setCookie">Set Cookie</button>
<input id="in2">
    <button id="getCookie">Get Cookie</button>

JavaScript

function createCookie(name, value, days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
    var expires = "; expires=" + date.toGMTString();
  } else var expires = "";
  document.cookie = name + "=" + value + expires + "; path=/";
}

function readCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');
  for (var i = 0; i < ca.length; i++) {
    var c = ca[i];
    while (c.charAt(0) == ' ') c = c.substring(1, c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
  }
  return null;
}

function eraseCookie(name) {
  createCookie(name, "", -1);
}
$('#setCookie').click(function() {
  createCookie('test', $('#in1').val(), 1);
})
$('#getCookie').click(function() {
$('#in2').val(readCookie('test'));
})
$('#in2').val(readCookie('test'));