js圆点滚动切换

<div class="slider">
  <div class="slides">
    <img src="image1.jpg" alt="Image 1">
    <img src="image2.jpg" alt="Image 2">
    <img src="image3.jpg" alt="Image 3">
  </div>
  <div class="dots">
    <span class="dot" onclick="currentSlide(1)"></span>
    <span class="dot" onclick="currentSlide(2)"></span>
    <span class="dot" onclick="currentSlide(3)"></span>
  </div>
</div>

.slider {
  position: relative;
  max-width: 600px;
  margin: auto;
}

.slides img {
  width: 100%;
  display: none;
}

.slides img.active {
  display: block;
}

.dots {
  text-align: center;
  position: absolute;
  bottom: 15px;
  width: 100%;
}

.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;
}

let slideIndex = 1;
showSlides(slideIndex);

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

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

function showSlides(n) {
  let i;
  const slides = document.getElementsByClassName("slides")[0].getElementsByTagName("img");
  const 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].classList.remove("active");
    dots[i].classList.remove("active");
  }
  slides[slideIndex - 1].classList.add("active");
  dots[slideIndex - 1].classList.add("active");
}