How to write palindrome in JavaScript

Question

I wonder how to write palindrome in javascript, where I input different words and program shows if word is palindrome or not. For example word noon is palindrome, while bad

Answer 1

Taking a stab at this. Kind of hard to measure performance, though.

function palin(word) {
    var i = 0,
        len = word.length - 1,
        max = word.length / 2 | 0;

    while (i < max) {
        if (word.charCodeAt(i) !== word.charCodeAt(len - i)) {
            return false;
        }
        i += 1;
    }
    return true;
}

My thinking is to use charCodeAt() instead charAt() with the hope that allocating a Number instead of a String will have better perf because Strings are variable length and might be more complex to allocate. Also, only iterating halfway through (as noted by sai) because that's all that's required. Also, if the length is odd (ex: 'aba'), the middle character is always ok.