String.prototype.charCodeAt()

w

<script>
    function wf(w) {
        console.log(w)
    }

    var w = 'ABC'.charCodeAt(0);
    wf(w)
    var w = '中'.charCodeAt(0);
    wf(w)
    var w = '浙江'.charCodeAt(1);
    wf(w)
    var w = '浙江'.charCodeAt(2);
    wf(w)
    var w = '浙江'.charCodeAt(-1);
    wf(w)
</script>