10最后一个字符的长度

<script>
        function lengthOfLastWord(s) {
            var a = s.match(/[A-Za-z]+/g);
            console.log(a)
            return a == null ? 0 : a[a.length - 1].length;
        }
        var s = "a "
        lengthOfLastWord(s)
    </script>