<input type="button" id="lay" onclick="settime(this)" value="adff">
var countdown=5;
function settime(val) {
if (countdown == 0) {
val.removeAttribute("disabled");
val.value="获取验证码";
countdown=5;
} else {
val.setAttribute("disabled", true);
val.value="重新发送(" + countdown + ")";
countdown--;
setTimeout(function() {
settime(val)
},1000)
}
}
效果如下图: