javascript 幻灯片代码(含自动播放)

HTML

 <div class="slideshow-container">
   <div class="mySlides fade">
     <div class="numbertext">1 / 3</div>
     <img src="https://c.runoob.com/wp-content/uploads/2017/01/img_mountains_wide.jpg" style="width:100%">
     <div class="text">文本 1</div>
   </div>

   <div class="mySlides fade">
     <div class="numbertext">2 / 3</div>
     <img src="https://c.runoob.com/wp-content/uploads/2017/01/img_fjords_wide.jpg" style="width:100%">
     <div class="text">文本 2</div>
   </div>

   <div class="mySlides fade">
     <div class="numbertext">3 / 3</div>
     <img src="https://c.runoob.com/wp-content/uploads/2017/01/img_nature_wide.jpg" style="width:100%">
     <div class="text">文本 3</div>
   </div>

 </div>
 <br>

 <div style="text-align:center">
   <span class="dot"></span>
   <span class="dot"></span>
   <span class="dot"></span>
 </div>

css

 * {box-sizing:border-box}
 body {font-family: Verdana,sans-serif;}
 .mySlides {display:none}
 /* 幻灯片容器 */
 .slideshow-container {
   max-width: 1000px;
   position: relative;
   margin: auto;
 }

 /* 下一张 & 上一张 按钮 */
 .prev, .next {
   cursor: pointer;
   position: absolute;
   top: 50%;
   width: auto;
   margin-top: -22px;
   padding: 16px;
   color: white;
   font-weight: bold;
   font-size: 18px;
   transition: 0.6s ease;
   border-radius: 0 3px 3px 0;
 }

 /* 定位 "下一张" 按钮靠右 */
 .next {
   right:;
   border-radius: 3px 0 0 3px;
 }

 /* On hover, add a black background color with a little bit see-through */
 .prev:hover, .next:hover {
   background-color: rgba(0,0,0,0.8);
 }

 /* 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 (1/3 等) */
 .numbertext {
   color: #f2f2f2;
   font-size: 12px;
   padding: 8px 12px;
   position: absolute;
   top:;
 }

 /* 标记符号 */
 .dot {
   cursor:pointer;
   height: 13px;
   width: 13px;
   margin: 0 2px;
   background-color: #bbb;
   border-radius: 50%;
   display: inline-block;
   transition: background-color 0.6s ease;
 }

 .active, .dot:hover {
   background-color: #717171;
 }

 /* 淡出动画 */
 .fade {
   -webkit-animation-name: fade;
   -webkit-animation-duration: 1.5s;
   animation-name: fade;
   animation-duration: 1.5s;
 }

 @-webkit-keyframes fade {
   from {opacity: .4}
   to {opacity:}
 }

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

JS

 var slideIndex = 0;
 showSlides();

 function showSlides() {
     var i;
     var slides = document.getElementsByClassName("mySlides");
     var dots = document.getElementsByClassName("dot");
     for (i = 0; i < slides.length; i++) {
        slides[i].style.display = "none";
     }
     slideIndex++;
     if (slideIndex > slides.length) {slideIndex = 1}
     for (i = 0; i < dots.length; i++) {
         dots[i].className = dots[i].className.replace(" active", "");
     }
     slides[slideIndex-1].style.display = "block";
     dots[slideIndex-1].className += " active";
     setTimeout(showSlides, 2000); // 切换时间为 2 秒
 }