JavaScript迭代

<script>
    var arr = ["1","2","3"];
    var diedai = (function(){
        var length = arr.length,
        index = 0;
        return {
            hasNext:function(){
                return index < length;
            },next:function(){
                var data = arr[index];
                index = index+1;
                return data;
            }
        }
    })();

    while(diedai.hasNext()){
        alert(diedai.next());
    }
</script>