活动班未显示

Question

我正在按照以下W3School示例中的说明进行幻灯片放映： https://www.w3schools.com/howto/howto_js_slideshow.asp

我遇到以下问题：刷新页面时未显示活动类。

这是问题的链接。

https://github.com/FrancoisXavierPelletier/Intermarium24.com/issues/1

最好的问候。

我试图修改第一个边距和宽度以适应需要，但是第二个和第三个图像没有显示此边距。

预期的更改：该代码应添加一个要显示的活动类，并默认显示它。这可以用Javascript完成。

结果：刷新页面时，第一张幻灯片应该处于活动状态，而不是不显示幻灯片。

这是我使用的Javascript代码：

var slideIndex = 1;
showSlides(slideIndex);

// Next/previous controls
function plusSlides(n) {
  showSlides(slideIndex += n);
}

// Thumbnail image controls
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";
}

*{
    margin: 0;
    padding; 0;
    background: darkslategrey;
}

body{
    font-family: arial, sans-serif;
}


h1{
    font-family: 'Crete Round', serif;
    font-size: 45px;
    color: whitesmoke;
}

.wrapper{
    width: 940px;
    margin: 0 auto;
    padding: 0 0;
}

.orange{
    color: orange;
}

header ul{
    list-style: none;
}

header a{
    text-decoration: none;
    color: whitesmoke;
    font-weight: bold;
    margin-right: 20px;
}

header{
    height:100px;
}

header h1{
    float: left;
    margin-top: 25px;
}

header nav{
    float: right; 
    margin-top: 50px;
}

header nav li
{
    display: inline-block;
}

header nav li a {
    text-transform: uppercase;
}

.clear{
    clear: both;
}

/* Slideshow */

.slideshow-container {
    max-width: 940px;
    position: relative;
    margin: auto;
    background: red;
  
}

.mySlides {
    display: none;
    height: 300px;
    width: 97.5%;
    border: 1px solid white;
    border-radius: 10px;
}

#slide1{
    background: url('images/img1.jpg') center;
}

#slide2{
    background: url('images/img1.jpg') center;
}

#slide3{
    background: url('images/img1.jpg') center;
}

.prev, .next {
  cursor: pointer;
  position: absolute;
  top: 40%;
  width: auto;
  margin-top: -22px;
  padding: 16px;
  color: white;
  font-weight: bold;
  font-size: 18px;
  transition: 0.6s ease;
  border-radius: 0 3px 3px 0;
  user-select: none;
}

.prev {
left: 150px;
border-radius: 3px 0 0 3px;
}

.next {
  right: 150px;
  border-radius: 3px 0 0 3px;
}

.prev:hover, .next:hover {
  background-color: rgba(0,0,0,0.8);
  border-radius: 3px 0 0 3px;
}

.text {
    color: #f2f2f2;
    font-size: 15px;
    padding: 8px 12px;
    margin-top: 237px;
    position: relative;
    width: 97.4%;
    text-align: justify;
    background: black;
    opacity: 0.8;
    border-bottom-left-radius: 10px;
    border-bottom-right-radius: 10px;
}

.numbertext {
  color: #f2f2f2;
  font-size: 12px;
  padding: 8px 12px;
  position: relative;
  top: 0;
  background: transparent;
}

.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}
}








/* Category */

.category{
    height: 200px;
    width: 172px;
    background: red;
    float: left;
    margin: 20px 5px;
    border: 1px solid white;
    border-radius: 5px;
    
}

#military{
    background: url('images/military.jpg') center;
}

#economy{
    background: url('images/economy.jpg') center;
}

#society{
    background: url('images/social.jpg') center;
}

#culture{
    background: url('images/culture.jpg') center;
}

#tech{
    background: url('images/tech.jpg') center;
}

h2{
    color: white;
    font-size: 20px;
    text-align: center;
    margin-top: 150px;
    padding: 5px;
    text-transform: uppercase;
    font-family: 'Crete Round', serif;
    background: black;
    opacity: 0.8;
    
}

/* footer */

footer{
    height: 250px;
    background-color: white;
}

.footer-div{
    background: white; 
    margin: 20px;
    float: left;
    width: 20%;
    height: 200px; 
}

h3{
    background: transparent;
    color: black;
    text-transform: uppercase;
    font-weight: bold;
    padding: 10px;
    margin-top: 10px; 
}

footer ul{
    list-style: none;
    background: white; 
}

footer li{
    padding: 5px;
    background: white;
}

footer a{
    background: white;
}

<!DOCTYPE html>

<html>
    <head>
        <meta charset = "utf-8">
        <title> Intermarium24.pl </title>
        <link href="http://fonts.googleapis.com/css?family=Crete+Round" rel="stylesheet">
        <link rel="stylesheet" href="style.css">
        <script src="myscript.js"></script>
    </head>

    <header>
        <div class="wrapper">
            <h1>Intermarium<span class="orange">24</span>.com</h1>
                <nav>
                    <ul>
                        <li><a href="#main-image">Home</a> </li>
                        <li><a href="#steps">Discover</a> </li>
                        <li><a href="#possibilities">Register</a> </li>
                        <li><a href="#contact">Login</a> </li>
                        <li><a href="#contact">Contact</a> </li>
                    </ul>
                </nav>
        </div>
        </header>
        <section id="slideshow">
            <div class="wrapper">
                <div id="slideshow-container">
                    <div class="mySlides fade" id="slide1">
                        <div class="numbertext">1 / 3</div>
                        <div class="text">Caption Text</div>
                    </div>

                    <div class="mySlides fade" id="slide2">
                        <div class="numbertext">2 / 3</div>
                        <div class="text">Caption Two</div>
                    </div>

                    <div class="mySlides fade" id="slide3">
                        <div class="numbertext">3 / 3</div>
                        <div class="text">Caption Three</div>
                    </div>
                    
                    <a class="prev" onclick="plusSlides(-1)">&#10094;</a>
                    <a class="next" onclick="plusSlides(1)">&#10095;</a>
                </div>
            </div>
        </section>
    
        <div class="clear"></div>
    
        <section id="Main-articles">  
           <div class="wrapper">
               <div class="category" id="military">
                    <h2>Military</h2>
               </div>
               <div class="category" id="economy">
                   <h2>Economy</h2>
               </div>
               <div class="category" id="society">
                   <h2>Society</h2>
               </div>
               <div class="category" id="culture">
                   <h2>Culture</h2>
               </div>
               <div class="category" id="tech">
                   <h2>Tech</h2>
               </div>
            </div>
            <div class="clear"></div>
        </section>
    
        <footer>
            <div class="wrapper">
                <div class="footer-div">
                    <h3> Main menu</h3>
                    <ul>
                        <li><a>Home </a></li>
                        <li><a>Discover </a></li>
                        <li><a>Register </a></li>
                        <li><a>Login </a></li>
                        <li><a>Contact</a></li>
                    </ul>
                </div>
                <div class="footer-div" id="footer-category">
                    <h3> Categories</h3>
                    <ul>
                        <li><a>Military </a></li>
                        <li><a>Economy </a></li>
                        <li><a>Social </a></li>
                        <li><a>Cultural </a></li>
                        <li><a>Tech</a></li>
                    </ul>
                </div>
                <div class="footer-div" id="footer-legal">
                <h3> Categories</h3>
                    <ul>
                        <li><a>Terms of Sales </a></li>
                        <li><a>Terms of Use </a></li>
                        <li><a>Privacy Policy </a></li>
                        <li><a>Legal Contact </a></li>
                    </ul>
                </div>
                <div class="footer-div" id="footer-socmed">
                    <h3> Social medias</h3>
                    <ul>
                        <li><a>Facebook </a></li>
                        <li><a>Twitter </a></li>
                        <li><a>Contact </a></li>
                    </ul>
                
                </div>
            </div>
        </footer>
    
</html>