Waypoint: Caesars Cipher

function rot13(encodedStr) {
  var codeArr = encodedStr.split("");  // String to Array
  var decodedArr = []; // Your Result goes here
  // Only change code below this line
  var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

  for (var c = 0; c < codeArr.length; c++) //Count the number of words in codeArr
    {
      var newWord = "";
      var newLetter = "";

      for (var i = 0; i < codeArr[c].length; i++) //Count the number of letters in codeArr[currentWord]
        {
          var letterCode = codeArr[c][i].charCodeAt(0); //Convert to ASCII Code

          if ((letterCode >= 65) && (letterCode <= 90)) //If the letter is A-Z
            {

              for (var a = 0; codeArr[c][i] !== alphabet[a]; a++) //Go through alphabet checking for current letter
                {
                  var newIndex = Math.abs(13 - a);
                  newLetter = alphabet[alphabet.length - newIndex];
                }

            }

          else
            {
              newLetter = codeArr[c][i];
            }
          newWord += newLetter; //Add the newLetter to the newWord
          newLetter = ""; //Clear the newLetter variable

        }
      decodedArr.push(newWord); //Add the newWord to the decodedArr
    }


  // Only change code above this line
  return decodedArr.join(""); // Array to String
}

// Change the inputs below to test
rot13("SERR PBQR PNZC");