cipher.html

<script src="http://crypto-js.googlecode.com/svn/tags/3.1.2/build/rollups/aes.js"></script>
<script>
function mkCipher(cipherModule, encoding) {
  var that = this;
  that.encrypt = cipherModule.encrypt;

  that.decrypt = function (data, passphrase) {
    var decrypted = cipherModule.decrypt(data, passphrase);
    return decrypted.toString(encoding);
  };

  return that;                                                                                        
}

(function () {                                                  
  var AES = mkCipher(CryptoJS.AES, CryptoJS.enc.Utf8);                                                  
  var data = "My secret message";                                                                       
  var passphrase = "booyah!";
  var encrypted = AES.encrypt(data, passphrase);
  alert("Encrypted: " + encrypted);
  alert("Decrypted: " + AES.decrypt(encrypted, passphrase));
})();
</script>