消息编码器/解码器

Question

我正在编码消息编码器/解码器，我遇到了encode_message，decode_message和get_cipher函数的问题，我不知道哪里出错了。我还附上说明作为评论。此外，如果有更简单的方法来编码字母数组的字符，请将其添加到答案中。

'use strict()';

function bind_events() {
  'use strict';

  $('#encode_msg').hide();
  $('#decode_msg').hide();

  // bind the event handler to the event. 
  $('#encode_msg').click(function() {
    encode_handler();
  });

  $('#decode_msg').click(function() {
    decode_handler();
  });

  var $keyword = $('#keyword');
  $($keyword).blur(function() {
    $('#encode_msg').hide();
    $('#decode_msg').hide();
    if ($(this).val().length > 0) {
      $('#encode_msg').show();
      $('#decode_msg').show();
    } else {
      $('#encode_msg').hide();
      $('#decode_msg').hide();
    }

  });

}

function update_display(header, message) {
  'use strict';

  return $('#display-message h2, p').text();
}

function get_keyword() {
  'use strict';

  return $('#keyword').val().split('');;
}


function get_message() {
  'use strict';

  return $('#message').val().split('');
}

/**
 * Input:   None
 * Output:  The cipher alphabet using the keyword. 
 *              The cipher contains all characters from a to z, A to Z 
 *              and punctuation /.,;:?! 
 *              The order of the letters will be mixed up. 
 * Process:
 * 0. the alphabet as an array. 
 *      * The alphabet must include all upper and lower case letters 
 *      * AND the following punctuation (/.,?;:!) 
 * 1. Create a variable to hold the keyword from the form. 
 * 2. Declare a variable called remaining_letters and initialize it to the keyword.
 *      * The keyword should be split into an array.  
 *      * The variable will hold the remaining letters from the original alphabet  
 *      (the alphabet ordered a to z) that are not in the keyword.
 * 3. Iterate through the length of the alphabet. 
 *      3.1 Get the index of the alphabet letter from the keyword. 
 *      3.2 If the index value is less than 0, push the letter from the alphabet
 *              onto the remaining_letters array 
 * 4. Return remaining_letters      
 */
function get_cipher() {
  'use strict';
  var alphabet = [A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, '/', '.', ',', ';', ':', '?', '!'];
  var $keyword = $('#keyword');
  var $remaining_letters = $keyword;
  $('$keyword').val().split('');

  for (i = 0; i < alphabet.length(); i++) {
    if (alphabet[i] == $keyword[j]) {
      if (j < 0) {
        remaining_letters.push(alphabet[i]);
      }
    }
  }

  return remaining_letters;

}


function encode_handler() {
  'use strict';
  var encoded_message = encode_message();
  update_display('Encoded Message', encoded_message);
}


function decode_handler() {
  'use strict';
  var decoded_message = decode_message();
  update_display('Decoded Message', decoded_message);
}

/**
 * Encode the message. 
 * Input:     None
 * Output:    The encrypted message.
 * Process:
 *        1. Required Variables:
 *            1. the cipher as an array
 *            2. the alphabet as an array. 
 *                * The alphabet must include all upper and lower case letters 
 *                * AND the following punctuation ( .,?;:!) - including the space
 *            3. the message from the form as an array
 *            4. an empty array variable that will hold the encoded message
 *     2. iterate through the length of the message.
 *         1. Find the index of the letter (message) in the alphabet.
 *         2. when the index value is positive (including 0) 
 *                 then get the corresponding letter from the cipher using the index
 *                 and push it onto the encoded message array.
 *             otherwise
 *                 push the letter (message) onto the encoded message array.
 *     3. return the encoded message array joined together.
 */
function encode_message() {
  'use strict';
  var cipher = [];
  var alphabet = [A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, '/', '.', ',', ';', ':', '?', '!'];
  var message = get_message();
  var encoded_message = [];

  for (i = 0; i < message.length(); i++) {
    if (message[i] == alphabet[j]) {
      if (j < 0) {
        encoded_message.push(message[i]);
      }
    }
  }

  return encoded_message.toString();
}

/**
 * Input:    None
 * Output:   The decrypted message.
 * Process:
 *       1. Required Variables:
 *           1. the cipher as an array
 *           2. the alphabet as an array. 
 *           3. the message from the form as an array
 *           4. an empty array variable that will hold the decoded message
 *       2. iterate through the length of the message.
 *           1. Find the index of the letter (message) in the cipher.
 *           2. when the index value is positive (including 0) 
 *                   then get the corresponding letter from the alphabet using the index
 *                   and push it onto the decoded message array.
 *               otherwise
 *                   push the letter (message) onto the decoded message array.
 *       3. return the decoded message array joined together.
 */
function decode_message() {
  'use strict';
  var cipher = [];
  var alphabet = [A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, '/', '.', ',', ';', ':', '?', '!'];
  var message = get_message();
  var decoded_message = [];
  for (i = 0; i < message.length(); i++) {
    if (message[i] == alphabet[j]) {
      if (j < 0) {
        decoded_message.push(message[i]);
      }
    }
  }

  return decoded_message.toString();
}

$(bind_events).ready();

如何编辑这些功能以使它们正常运行？