倒计时隐藏/显示div

html部分：

<div class="subtdbg">
<button type="button" id="daoshu" disabled=""></button>
</div>

jquery部分：

<script type="text/javascript">
var i = 8;
var time = setInterval("daoshu()",1000);
function daoshu(){
i--;
if(i==0){
$("#daoshu").html("下一步");
$().removeAttr('disabled');
clearInterval(time);
}else{
$("#daoshu").html("我已阅读("+i+")");
}
} 
</script>