leetcode 9. Palindrome Number

var isPalindrome = function(x) {
    if (x < 0) {
        return false;
    }
    if (x < 10) {
        return true;
    }
    var s = x + '';
    var l = s.length;
    l = l - 1;
    var start = 0;
    var end = l;
    while (start < end) {
        if (s[start] == s[end]) {

        } else {
            return false;
        }
        start++;
        end--;
    }
    return true;
};