Palindrome Checker回文检查

 Return true if the given string is a palindrome. Otherwise, return false.

A palindrome is a word or sentence that's spelled the same way both forward and backward, ignoring punctuation, case, and spacing.

Note: You'll need to remove all non-alphanumeric characters (punctuation, spaces and symbols) and turn everything into the same case (lower or upper case) in order to check for palindromes.

主要思路是，把字符串转换为一个数组，然里利用数组的reverse()方法，得到一个新的数组，这个新的数组再合成字符串，和原来的字符串进行比较。

function palindrome(str) {

  var pattern = /[^a-z0-9A-Z]/gi;

  var newstr = str.replace(pattern,"").toLowerCase();

  console.log(newstr);

  var newarr = newstr.split("").reverse();

  console.log(newarr);

  var reversedStr = newarr.join("");

  console.log(reversedStr);

  if (reversedStr==newstr)

  {

    return true;

  } 

  return false;

}

palindrome("eye");