js,JQ获取短信验证码倒计时

按钮

<a href="javasript:void(0);"onclick="settime(this);">获取手机验证码</a>

倒计时js

    <script>
        var countdown=60;
        function settime(obj) {
            if (countdown == 0) {
                obj.getAttributeNode('onclick').value ="settime(this);";
                obj.textContent="免费获取验证码";
                countdown = 60;
                return;
            } else {
                obj.getAttributeNode('onclick').value ="javascript:void(0);";
                obj.setAttribute("disabled", true);
                obj.textContent="重新发送(" + countdown + ")";
                countdown--;
            }
        setTimeout(function() {
            settime(obj)
            },1000)
        }
    </script>