测试题

<script>
        var str=‘afsbgudafdahawysavfaafsrghavbxrsah‘;
        var json={};
        for (var i = 0; i < str.length; i++) {
            var key=str[i];
            if (!json[key]) {
                json[key]=1;
            }else{
                json[key]++;
            }
        }
        var a=0,b;
        for (var x in json) {
            if (json[x]>a) {
                a=json[x];
                b=x;
            }
        }
        console.log(a);
        console.log(b);
    </script>