js 发送短信验证码倒计时

html

<input type="button" id="btn" value="免费获取验证码" onclick="settime(this)" />

js

// 短信验证码倒计时var countdown=60;function settime(obj) {    if (countdown == 0) {        obj.removeAttribute("disabled");        obj.value="免费获取验证码";        countdown = 60;        return;    } else {        obj.setAttribute("disabled", true);        obj.value="重新发送(" + countdown + ")";        countdown--;    }    setTimeout(function() {            settime(obj) }        ,1000)}

原文地址：https://www.cnblogs.com/shuihanxiao/p/9813144.html