W3School TIY Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
* {box-sizing: border-box;}
body {font-family: Verdana, sans-serif;}
.mySlides {display: none;}
img {vertical-align: middle;}

/* 幻灯片容器 */
.slideshow-container {
  max-width: 1000px;
  position: relative;
  margin: auto;
}

/* 标题文本 */
.text {
  color: #f2f2f2;
  font-size: 15px;
  padding: 8px 12px;
  position: absolute;
  bottom: 8px;
  width: 100%;
  text-align: center;
}

/* 数字文本 (1/4 等) */
.numbertext {
  color: #f2f2f2;
  font-size: 12px;
  padding: 8px 12px;
  position: absolute;
  top: 0;
}

/* 圆点/子弹/指示器 */
.dot {
  height: 15px;
  width: 15px;
  margin: 0 2px;
  background-color: #bbb;
  border-radius: 50%;
  display: inline-block;
  transition: background-color 0.6s ease;
}

.active {
  background-color: #717171;
}

/* 渐隐动画 */
.fade {
  animation-name: fade;
  animation-duration: 1.5s;
}

@keyframes fade {
  from {opacity: .4} 
  to {opacity: 1}
}

/* 在小屏幕上，减小文字大小 */
@media only screen and (max-width: 300px) {
  .text {font-size: 11px}
}
</style>
</head>
<body>

<h2>自动幻灯片播放</h2>
<p>每 2 秒更换一次图片：</p>

<div class="mySlides fade">
  <div class="numbertext">1 / 4</div>
  <img src="/i/photo/beijing.jpg" style="width:100%;">
  <div class="text">Caption Text</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">2 / 4</div>
  <img src="/i/photo/shanghai.jpg" style="width:100%;">
  <div class="text">Caption Two</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">3 / 4</div>
  <img src="/i/photo/wuhan.jpg" style="width:100%;">
  <div class="text">Caption Three</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">4 / 4</div>
  <img src="/i/photo/shanghai-1.jpg" style="width:100%;">
  <div class="text">Caption Four</div>
</div>

</div>
<br>

</body>
</html>