写一个小程序的轮播图代码

好的，以下是一个简单的轮播图代码示例，使用了 HTML、CSS 和 JavaScript：

HTML:

<div class="slideshow-container">
  <div class="mySlides fade">
    <img src="img1.jpg" style="width:100%">
  </div>
  <div class="mySlides fade">
    <img src="img2.jpg" style="width:100%">
  </div>
  <div class="mySlides fade">
    <img src="img3.jpg" style="width:100%">
  </div>
</div>

CSS:

.slideshow-container {
  max-width: 1000px;
  position: relative;
  margin: auto;
}

.mySlides {
  display: none;
}

.prev, .next {
  cursor: pointer;
  position: absolute;
  top: 50%;
  width: auto;
  padding: 16px;
  margin-top: -22px;
  color: white;
  font-weight: bold;
  font-size: 18px;
  transition: 0.6s ease;
  border-radius: 0 3px 3px 0;
  user-select: none;
}

.next {
  right: 0;
  border-radius: 3px 0 0 3px;
}

.prev:hover, .next:hover {
  background-color: rgba(0,0,0,0.8);
}

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

.dot-container {
  text-align: center;
  padding: 20px;
  background: #ddd;
}

.dot {
  cursor: pointer;
  height: 15px;
  width: 15px;
  margin: 0 2px;
  background-color: #bbb;
  border-radius: 50%;
  display: inline-block;
  transition: background-color 0.6s ease;
}

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

.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: 1}
}

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

JavaScript:

var slideIndex = 1;
showSlides(slideIndex);

function plusSlides(n) {
  showSlides(slideIndex += n);
}

function currentSlide(n) {
  showSlides(slideIndex = n);
}

function showSlides(n) {
  var i;
  var slides = document.getElementsByClassName("mySlides");
  var dots = document.getElementsByClassName("dot");
  if (n > slides.length) {slideIndex = 1}
  if (n < 1) {slideIndex = slides.length}
  for (i = 0; i < slides.length; i++) {
      slides[i].style.display = "none";
  }
  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";
}

这段代码使用了 JavaScript 来控制图片的显示和轮播。其中，`showSlides()` 函数控制轮播的逻辑，`plusSlides()` 函数和 `currentSlide()` 函数则是用来控制向前或向后移动轮播的。CSS 部分则控制了轮播图的样式，包括图片的大小、文字的位置、前后按钮的样式等等。