Determine if a given string is a palindrome

palindrome.js

var input_str = 'madam';
 
function checkIfPalindrome(str) {
  if (str == str.split('').reverse().join('')) {
    alert('Yup, ' + str +  'is a palindrome');
  } else {
    alert('Nope, ' + str + ' isn\'t a palindrome');
  }
}

checkIfPalindrome(input_str);