<div class="box">
        <label for="">手机号</label> <input type="number"> <button>获取</button>
    </div>

 1 var btn = document.querySelector('button')
 2         var time = 10;
 3         btn.addEventListener('click', function () {
 4             this.disabled = true;
 5             var timer = setInterval(function () {
 6                 if (time == 0) { 7  clearTimeout(timer) 8 btn.disabled = false; 9 btn.innerHTML = '发送' 10 time = 10; 11 } else { 12 btn.innerHTML = '还剩下' + time + '秒' 13 time--; 14  } 15 }, 1000) 16 })