Get cookie value (must be same domain)

GetCookie.js

var getCookie = function (key) {
  var cookies = document.cookie.split(';');
  for (var i = 0; i < cookies.length; ++i) {
    var currentKey = cookies[i].substr(0, cookies[i].indexOf('='));
    currentKey = currentKey.replace(/^\s+|\s+$/g, "");

    if (currentKey === key) {
      return cookies[i].substr(cookies[i].indexOf('=') + 1);
    }
  }

  return '';
}