checking for palindromes in javascript integers 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: js palindrome number

isPalindrome = function(x) {
    if (x < 0) {
        return false;
    }
    
    return x === reversedInteger(x, 0);
};

reversedInteger = function(x, reversed) {
    if(x<=0) return reversed;
        reversed = (reversed * 10) + (x % 10);
        x = Math.floor(x / 10);
    
    return reversedInteger(x, reversed);
};