点击按钮出现60秒倒计时，JS（按钮）

<script type="text/javascript">
        var countdown=60;
        function settime(val) {
            var e = $('#email').val();
            //对电子邮件的验证
            var myreg = /^([a-zA-Z0-9]+[_|\_|.]?)*[a-zA-Z0-9]+@([a-zA-Z0-9]+[_|\_|.]?)*[a-zA-Z0-9]+.[a-zA-Z]{2,3}$/;
            if(!myreg.test(e))
            {
                return;
            }
            if (countdown == 0) {
                val.removeAttribute("disabled");
                val.value="获取验证码";
                countdown = 60;
                return;
            } else {
                val.setAttribute("disabled", true);
                val.value="重新发送(" + countdown + ")";
                countdown--;
            }
            setTimeout(function() {
                settime(val)
            },1000)
        }
    </script>