jQuery+css做一个倒计时进度条

如何利用jQuery+css做一个倒计时进度条，下面web建站小编给大家简单介绍一下具体实现代码！

html代码：

<div class="progress-bar">
  <div class="item"></div>
</div>
<div class="btn">进度条</div>

<div class="count-down">
  <div class="item"></div>
</div>
<div>剩余时间 ： <span class="time"></span>s</div>

css代码：

.progress-bar {
  width:200px;
  height:20px;
  background-color:aliceblue;
  border-radius:20px;
  display:flex;
}
.btn {
  margin:20px;
  width:70px;
  height:30px;
  line-height:30px;
  text-align:center;
  background-color:#bfa;
  cursor:pointer;
  color:rgb(202,202,90);
}
.progress-bar .item {
  width:0;
  height:100%;
  background-color:rgb(56,148,255);
  border-radius:20px;
  transition:all 1s;
}
.count-down {
  width:200px;
  height:20px;
  background-color:aliceblue;
  border-radius:20px;
  display:flex;
}
.count-down .item {
  width:100%;
  height:100%;
  background-color:rgb(56,148,255);
  border-radius:20px;
  transition:all 0.1s;
}

jquery代码：

var w = 0
let w2 = 100
let t = 50
$('.time').html(t)
$('.btn').on("click", function() {
  w += 20
  $('.progress-bar .item').css("width", `${w}%`)
  console.log(w);
})


let timer = setInterval(() => {
  w2 -= 0.2
  if (w2 < 0) {
    clearInterval(timer)
  }
  console.log(w2);
  $('.count-down .item').css("width", `${w2}%`)
}, 100);
let timer2 = setInterval(() => {
  t -= 1
  if (t <= 0) {
    clearInterval(timer2)
  }
  $('.time').html(t)
}, 1000);