Question

我正在尝试在自动幻灯片放映中显示多个图像。尽管不会更改为下一幅图像，但确实会显示第一幅图像。

    var slides = 0;
    Displayslides();
    
    function Displayslides() {
      var j;
      var slideshow = document.getElementsByClassName("myslides");
      var dots = document.getElementsByClassName("dot");
      for (j = 0; j < slidesshow.length; j++) {
        slides[j].style.display = "none";  
      }
      slides++;
      if (slides > slideshow.length) {slides = 1}    
      for (j = 0; j < dots.length; j++) {
        dots[j].className = dots[j].className.replace(" active", "");
      }
    }

<div class="slideshow-container">
    
    <div class="myslideshow fade">
      <img src="img_natural1.jpg" style="width:100%">
    </div>
    
    <div class=" myslideshow fade">
      <img src="img_natural2.jpg" style="width:100%">
    </div>
    
    <div class="myslideshow fade">
      <img src="img_natural3.jpg" style="width:100%">
    </div>
    <br>
</div>

任何帮助将不胜感激。

Answer 1

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";
}

* {box-sizing: border-box}
body {font-family: Verdana, sans-serif; margin:0}
.mySlides {display: none}
img {vertical-align: middle;}

/* Slideshow container */
.slideshow-container {https://www.w3schools.com/howto/img_nature_wide.jpg
  max-width: 1000px;
  position: relative;
  margin: auto;
}

/* Next & previous buttons */
.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;
}

/* Position the "next button" to the right */
.next {
  right: 0;
  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);
}

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

/* Number text (1/3 etc) */
.numbertext {
  color: #f2f2f2;
  font-size: 12px;
  padding: 8px 12px;
  position: absolute;
  top: 0;
}

/* The dots/bullets/indicators */
.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;
}

/* Fading animation */
.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}
}

/* On smaller screens, decrease text size */
@media only screen and (max-width: 300px) {
  .prev, .next,.text {font-size: 11px}
}

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">

</head>
<body>

<div class="slideshow-container">

<div class="mySlides fade">
  <div class="numbertext">1 / 3</div>
  <img src="https://image.shutterstock.com/image-photo/beautiful-water-drop-on-dandelion-260nw-789676552.jpg" style="width:100%">
  <div class="text">Caption Text</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">2 / 3</div>
  <img src="https://media.gettyimages.com/photos/spring-field-picture-id539016480?s=612x612" style="width:100%">
  <div class="text">Caption Two</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">3 / 3</div>
  <img src="https://images.pexels.com/photos/462118/pexels-photo-462118.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500" style="width:100%">
  <div class="text">Caption Three</div>
</div>

<a class="prev" onclick="plusSlides(-1)">&#10094;</a>
<a class="next" onclick="plusSlides(1)">&#10095;</a>

</div>
<br>

<div style="text-align:center">
  <span class="dot" onclick="currentSlide(1)"></span> 
  <span class="dot" onclick="currentSlide(2)"></span> 
  <span class="dot" onclick="currentSlide(3)"></span> 
</div>



</body>
</html>

Visit W3 School

Answer 2

W3Schools中的简化示例：

示例div（添加更多子div以获取更多图像）

<div class="slideshow-container">
<div class="mySlides fade">
  <div class="numbertext">1 / 2</div>
  <img src="https://www.w3schools.com/howto/img_snow_wide.jpg" style="width:100%">
  <div class="text">Caption Text</div>
</div>
</div>

Javascript：

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); // Change image every 2 seconds
}

如何显示自动幻灯片

2 个答案: