javascript实现页面倒计时跳转

<script type="text/javascript">    var t = 5;//设定跳转的时间    setInterval("refer()", 1000); //启动1秒定时    function refer() {        if (t == 0) {        location = "three.jsp"; //设定跳转的链接地址        }        document.getElementById('show').innerHTML ="登录成功！！！"+ t + "秒后跳转到three.jsp页面"; //显示倒计时        t--; //计数器递减    }    </script>