Jquery验证码倒计时

<input type="button"  value="获取验证码"  id="getCode" style="color:#4664E6;background:white;" />

 <script type="text/javascript">
        var countdown = 60;
        $(function () {
            $("#getCode").bind("click", function () {
                settime();
            });
        })
        function settime(e) {
            if (countdown == 0) {
                countdown = 60;
                $("#getCode").val("获取验证码");
                $("#getCode").removeAttr("disabled");
                return false;
            } else {
                countdown--;
                $("#getCode").val(countdown + "秒后重新获取");
                $("#getCode").attr("disabled", "disabled");
            }
            setTimeout(function () {
                settime();
            }, 1000);
        }
    </script>