palindrome.js

function isPalindrome(string) {
  string = ""+string;
  
  var len = string.length;
  
  if (len<=1) {
    return true;
  }
  
  if (string[0] === string[len-1])
    return iiPalindrome(string.slice(1, -1));
  
  return false;
}

var string = "racecar";
console.log(isPalindrome(string));