Retrieve A Cookie With Javascript

getCookie.js

function getCookie(cookieName) {
  var name = cookieName + '='
  var arr = document.cookie.split(';')

  for (var i = 0; i < arr.length; i++) {
    var str = arr[i]

    while (str.charAt(0) === ' ') {
      str = str.substring(1)
    }

    if (str.indexOf(name) === 0) {
      return str.substring(name.length, str.length)
    }
  }
  return ''
}