Question

我使用以下代码进行幻灯片放映，幻灯片放映的性能非常适合我的网站，我不打算使用其他代码或其他插件。

我会为此幻灯片添加两个功能：

我想在5秒后自动更改图像。
当鼠标停留在当前图像上时，暂停相同的图像。

请指导我！感谢

如果您打算将代码从JavaScript更改为jQuery，则没有任何障碍。 的代码：

＆＃13;

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";
}

＆＃13;

* {box-sizing:border-box}
body {font-family: Verdana,sans-serif;margin:0}
.mySlides {display:none}

/* Slideshow container */
.slideshow-container {
  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;
}

/* 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: 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;
}

/* 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}
}

＆＃13;

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>

</style>
</head>
<body>

<div class="slideshow-container">

<div class="mySlides fade">
  <div class="numbertext">1 / 3</div>
  <img src="https://www.w3schools.com/howto/img_nature_wide.jpg" style="width:100%">
  <div class="text">Caption Text</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">2 / 3</div>
  <img src="https://www.w3schools.com/howto/img_fjords_wide.jpg" style="width:100%">
  <div class="text">Caption Two</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">3 / 3</div>
  <img src="https://www.w3schools.com/howto/img_mountains_wide.jpg" 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>

<script>

</script>

</body>
</html>

＆＃13;

Answer 1

我将幻灯片容器div更改为具有ID而不是类，因为我可以执行document.getElementById并检索该特定元素而不是数组（如果我要执行document.getElementByClassName：

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

</style>
</head>
<body>

<div id="slideshow-container">

<div class="mySlides fade">
  <div class="numbertext">1 / 3</div>
  <img src="https://www.w3schools.com/howto/img_nature_wide.jpg" 
  style="width:100%">
<div class="text">Caption Text</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">2 / 3</div>
  <img src="https://www.w3schools.com/howto/img_fjords_wide.jpg" 
style="width:100%">
  <div class="text">Caption Two</div>
</div>

<div class="mySlides fade">
  <div class="numbertext">3 / 3</div>
  <img src="https://www.w3schools.com/howto/img_mountains_wide.jpg" 
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>

<script>

</script>

</body>
</html>

然后我添加了一个全局计时器，它将每5秒调用一次plusSlide函数。然后我在＆＃34; mouseleave＆＃34;上使用clearInterval。停止计时器。请注意，要使用clearInterval（计时器），我必须先将setInterval保存到全局变量timer。

var timer = setInterval(function(){plusSlides(1)}, 5000 );

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";
}

document.getElementById("slideshow-container").addEventListener("mouseover", 
 function(){
    clearInterval(timer)
 });
document.getElementById("slideshow-container").addEventListener("mouseleave", function(){
timer = setInterval(function(){plusSlides(1)}, 5000 );
});

没有插件和框架的幻灯片图像

1 个答案: