javascript 数组循环 和 操作父元素问题

[color=blue][b][size=medium]js部分[/size][/b][/color][code="java"]

<style>
    .jj{
        width:100px;height:60px;
    }
</style>
<script type="text/javascript">
    $(document).ready(function() {
        var array = new Array();
        array = document.getElementsByName("counts");
        var i=0;
        while(i<array.length){
            var cou_1 = parseInt(array[i].getAttribute("cou_1"));
            var cou_2 = parseInt(array[i].getAttribute("cou_2"));
            //array[i].previousSbiling.innerHTML="--"+(cou_1+cou_2);
            array[i].parentNode.innerHTML="-----"+cou_1;
            //alert(array[i].parentNode.innerHTML)
            //alert(x.parentNode.getAttribute("id"));


            i++;
        }
    });
</script>

[/code]

[b][size=medium][color=blue]页面部分[/color][/size][/b]
[code="java"]

<div id="a2" class="jj" style="background-color:#E7ABAB">
    <input type="hidden" id="cou_2" name="counts" cou_1="10" cou_2="12" />
</div>
<div id="a3" class="jj" style="background-color:#E7ABAB">
    <input type="hidden" id="cou_3" name="counts" cou_1="10" cou_2="12" />
</div>
<div id="a4" class="jj" style="background-color:#E7ABAB">
    <input type="hidden" id="cou_4" name="counts" cou_1="10" cou_2="12" />
</div>

[/code]
[color=blue][size=medium][b]
效果不一样啊，控制台不报错[/b][/size][/color]
[img]http://dl.iteye.com/upload/picture/pic/131615/6bab4efe-cfe5-3bc2-90a1-8e6f4710affd.png[/img]

测试：
直接alert()父元素的id值 没问题，为啥 给父元素 添加内容出现 跳步现象了啊？？？
[img]http://dl.iteye.com/upload/picture/pic/131617/38bf1cf4-9975-3313-b54c-e6af12b853e6.gif[/img]
[color=red][size=x-large][b] 求指教！！！[/b][/size][/color]