validation.js

var customValidations = (function() {
  function reverse(word) {
    var i, reversedLetters = [];
    for (i = word.length - 1; i >= 0; i--) {
      reversedLetters.push(word[i]);
    }
    return reversedLetters.join('');
  }

  return {
    isPalindrome: function(word) {
      return reverse(word) === word;
    }
  }
})();

$.validator.addMethod("palindrome", function(value) {
  return customValidations.isPalindrome(value);
});

$("#exampleForm").validate();