how to find palindromes in js code example

Example 1: palindrome in javascript

function palindrome(str) {

    var len = str.length;
    var mid = Math.floor(len/2);

    for ( var i = 0; i < mid; i++ ) {
        if (str[i] !== str[len - 1 - i]) {
            return false;
        }
    }

    return true;
}

Example 2: palindrome javascript

function palindrome(str) {
 var splitted = str.split("");
 var reversed = splitted.reverse("");
 var joined = reversed.join("");
 return joined.toLowerCase().replace(/[^0-9a-z]/gi, '') == str.toLowerCase().replace(/[^0-9a-z]/gi, '')
}