javascript - 如何使用 Javascript 将计时器添加到轮播滑块
问题描述
我有一个带有文本的轮播滑块。我对这些滑块有自己的自定义 js。轮播箭头工作正常,但我希望滑块在一段时间后自行移动。
这是HTML
<div class="col-6 col-xs-12 " style="text-align:-webkit-center;">
<div class="slideshow-container">
<div class="mySlides w3-container w3-center w3-animate-right">
<h2 class="font-size" id="f37" data-animation="fadeInUp" data-delay="200ms">1</h2>
</div>
<div class="mySlides w3-container w3-center w3-animate-right">
<h2 class="font-size" id="f37" data-animation="fadeInUp" data-delay="200ms">2</h2>
</div>
<div class="mySlides w3-container w3-center w3-animate-right">
<h2 class="font-size" id="f37" data-animation="fadeInUp" data-delay="200ms">3</h2>
</div>
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
</div>
</div>
这是JS
<script>
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";
}
</script>
希望我对这个问题很清楚。非常感谢您的回答。我已经将代码更新为 codepen,当我点击箭头时,您可以观察到它的奇怪行为,尽管自动幻灯片在空闲时工作正常。 https://codepen.io/mahirq8/pen/JjjJzbe
谢谢
解决方案
你会用setTimeout
它。
timer
在脚本顶部添加一个变量:
var timer;
在你的 functionshowSlides
中,添加以下两行(任何地方,比如在它的末尾):
clearTimeout(timer);
timer = setTimeout(() => plusSlides(1), 2000);
如果您现在仍然使用箭头按钮,计时器将重置并在您最后一次干扰后 2 秒再次继续滑动幻灯片。
你可以在这里运行它:
var timer;
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";
}
slides[slideIndex - 1].style.display = "block";
clearTimeout(timer);
timer = setTimeout(() => plusSlides(1), 2000);
}
* {box-sizing: border-box}
body {font-family: Verdana, sans-serif; margin:0}
.mySlides {display: none}
img {vertical-align: middle;}
/* 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: red;
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}
}
<div class="slideshow-container">
<div class="mySlides fade">
<h1>111</h1>
<div class="text">Caption Text</div>
</div>
<div class="mySlides fade">
<h1>222</h1>
<div class="text">Caption Two</div>
</div>
<div class="mySlides fade">
<h1>333</h1>
<div class="text">Caption Three</div>
</div>
<div class="mySlides fade">
<h1>444</h1>
<div class="text">Caption Three</div>
</div>
<div class="mySlides fade">
<h1>555</h1>
<div class="text">Caption Three</div>
</div>
<a class="prev" onclick="plusSlides(-1)">❮</a>
<a class="next" onclick="plusSlides(1)">❯</a>
</div>
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