w3.css幻灯片：如何添加自动幻灯片功能

Question

我想将此幻灯片演示从w3.css库制作为每4-5秒自动进行一次幻灯片演示。 也可以在w3schools编辑器中找到。

w3.css幻灯片的更多文档可以在这里找到

我需要以某种方式添加此代码以使图像自动幻灯片显示，但要保留项目符号背景并使箭头起作用：

var slideIndex = 0;
carousel();
function carousel() {
    var i;
    var x = document.getElementsByClassName("mySlides");
    for (i = 0; i < x.length; i++) {
      x[i].style.display = "none"; 
    }
    slideIndex++;
    if (slideIndex > x.length) {slideIndex = 1} 
    x[slideIndex-1].style.display = "block"; 
    setTimeout(carousel, 2000); // Change image every 2 seconds
}

这是完整的代码：

 var slideIndex = 1; showDivs(slideIndex); function plusDivs(n) { showDivs(slideIndex += n); } function currentDiv(n) { showDivs(slideIndex = n); } function showDivs(n) { var i; var x = document.getElementsByClassName("mySlides"); var dots = document.getElementsByClassName("demo"); if (n > x.length) {slideIndex = 1} if (n < 1) {slideIndex = x.length} for (i = 0; i < x.length; i++) { x[i].style.display = "none"; } for (i = 0; i < dots.length; i++) { dots[i].className = dots[i].className.replace(" w3-white", ""); } x[slideIndex-1].style.display = "block"; dots[slideIndex-1].className += " w3-white"; } 

 .mySlides {display:none} .w3-left, .w3-right, .w3-badge {cursor:pointer} .w3-badge {height:13px;width:13px;padding:0} 

 <link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css"> <div class="w3-container"> <h2>Slideshow Indicators</h2> <p>An example of using buttons to indicate how many slides there are in the slideshow, and which slide the user is currently viewing.</p> </div> <div class="w3-content w3-display-container" style="max-width:800px"> <img class="mySlides" src="https://cdn-s3.si.com/styles/marquee_large_2x/s3/images/trump-5.jpg" style="width:100%"> <img class="mySlides" src="https://i.ytimg.com/vi/VpevTNRK-_M/maxresdefault.jpg" style="width:100%"> <img class="mySlides" src="https://img00.deviantart.net/a73e/i/2015/261/4/3/the_magic_world_by_chibionpu-d4ol7wm.jpg" style="width:100%"> <div class="w3-center w3-container w3-section w3-large w3-text-white w3-display-bottommiddle" style="width:100%"> <div class="w3-left w3-hover-text-khaki" onclick="plusDivs(-1)">&#10094;</div> <div class="w3-right w3-hover-text-khaki" onclick="plusDivs(1)">&#10095;</div> <span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(1)"></span> <span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(2)"></span> <span class="w3-badge demo w3-border w3-transparent w3-hover-white" onclick="currentDiv(3)"></span> </div> </div> 

Answer 1

setInterval(function(){
    slideIndex++;
    currentDiv(slideIndex);
}, 2000);

最后将其添加到您的代码示例中