var canRequest = true
function postData () {
  if (!canRequest) return
  fetch(url)
  .then(res => {
    canRequest = true  
  })
  .catch(e => {
    canRequest = true
  })
  canRequest = false
}

<div id="count">获取验证码</div>

body {
    display: flex;
    height: 100vh;
}
#count {
    margin: auto;
    padding: 10px;
    width: 100px;
    border: 1px solid;
    text-align: center;
    cursor: pointer;
    border-radius: 4px;
}
.disable {
    pointer-events: none;
    color: #666;
}

const count = document.getElementById('count')
const tip = count.textContent
count.onclick = e => {
    console.log(111)
    count.classList.add('disable')
    count.textContent = 10
    var id = setInterval(() => {
        count.textContent--
        if (count.textContent <= 0) {
            count.classList.remove('disable')
            count.textContent = tip
            clearInterval(id)
        }
    }, 1000)
}