javascript - 使用 javascript 代码显示和隐藏部分的问题不起作用

Question

各位，我对 javascript 和 HTML 部分有疑问。

我需要点击向下箭头才能从第一个变为另一个等等。不幸的是，代码没有反应，所以我真的不知道如何解决。

为了更好地概览而缩短的代码。

主要问题在 javascript 中

HTML

HTML 足够好，可以更好地定位。

  <section> <div style="width:40px; height:40px; background-color:black;" onclick="bottomscroll()"> </section>
  <section > <h1>text</h1></section>

  <section> <h1>text</h1></section>

  <section> <h1>text</h1></section>

  <section> <h1>text</h1></section>

CSS

我还缩短了 CSS 以获得更好的概览

.display-block { display:block; }
.display-none { display:none; } 

#fullpage { overflow: hidden; margin: 0; padding: 0;

}

#fullpage section { min-height: 100%; }

#fullpage section h4 { margin: 0; padding: 0; }

#fullpage section:nth-child(1)
{
   color:black;
    background:url(/img/fabian-grohs-597395-unsplash.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    height: 100vh;
}

#fullpage section:nth-child(1) h1
{
    margin: 0;
    padding: 0;
    color:whitesmoke;
    text-align: center;
    padding: 70px;
    font-family: 'Montserrat', sans-serif;
    font-size:40px;
}




#fullpage section:nth-child(1) p
{
    text-align: center;
    color:white;
    font-size:18px;
    width: 70%;
    margin:0 auto;
    font-family: 'Inconsolata', monospace;
    position: relative;
}

#fullpage section:nth-child(2)
{
    color:#333;
    background: white;
    min-height: 100vh;
}


#fullpage section:nth-child(2) h1
{
    margin: 0;
    padding: 0;
    color:#333;
    text-align: center;
    padding: 20px 0px;
    font-family: 'Montserrat', sans-serif;
}

#fullpage section:nth-child(3)
{
    color:black;
    background: green;
    min-height: 100vh;
}
#fullpage section:nth-child(4)
{
    color:black;
    background: green;
    min-height: 100vh;
}

#fullpage section:nth-child(5)
{
    color:black;
    background: green;
    min-height: 100vh;
}

Javascript

主要问题在 javascript 中

var page = 1;

function topscroll()
{
        if(page != 1)
        {
        page -= 1;    
        var page = document.querySelector("#fullpage section:nth-child("+page")");
            for(i = 0; i < 5; i++)
            {
            var pagehidden = document.querySelector("#fullpage section:nth-child("+i")"); 
            pagehidden.classList.add("display-none");   
            pagehidden.classList.remove("display-block");     
            }
        page.classList.add("display-block");    
        }
}

function bottomscroll()
{
        if(page != 5)
        {
        page += 1;    
        var page = document.querySelector("#fullpage section:nth-child("+page")");
            for(i = 0; i < 5; i++)
            {
            var pagehidden = document.querySelector("#fullpage section:nth-child("+i")"); 
            pagehidden.classList.add("display-none");  
            pagehidden.classList.remove("display-block");   
            }
        page.classList.add("display-block");    
        }
}

var page = 1;

function topscroll()
{
        if(page != 1)
        {
        page -= 1;    
        var page = document.querySelector("#fullpage section:nth-child("+page")");
            for(i = 0; i < 5; i++)
            {
            var pagehidden = document.querySelector("#fullpage section:nth-child("+i")"); 
            pagehidden.classList.add("display-none");   
            pagehidden.classList.remove("display-block");     
            }
        page.classList.add("display-block");    
        }
}

function bottomscroll()
{
        if(page != 5)
        {
        page += 1;    
        var page = document.querySelector("#fullpage section:nth-child("+page")");
            for(i = 0; i < 5; i++)
            {
            var pagehidden = document.querySelector("#fullpage section:nth-child("+i")"); 
            pagehidden.classList.add("display-none");  
            pagehidden.classList.remove("display-block");   
            }
        page.classList.add("display-block");    
        }
}

.display-block { display:block; }
.display-none { display:none; } 

#fullpage { overflow: hidden; margin: 0; padding: 0;

}

#fullpage section { min-height: 100%; }

#fullpage section h4 { margin: 0; padding: 0; }

#fullpage section:nth-child(1)
{
   color:black;
    background:url(/img/fabian-grohs-597395-unsplash.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    height: 100vh;
}

#fullpage section:nth-child(1) h1
{
    margin: 0;
    padding: 0;
    color:whitesmoke;
    text-align: center;
    padding: 70px;
    font-family: 'Montserrat', sans-serif;
    font-size:40px;
}




#fullpage section:nth-child(1) p
{
    text-align: center;
    color:white;
    font-size:18px;
    width: 70%;
    margin:0 auto;
    font-family: 'Inconsolata', monospace;
    position: relative;
}

#fullpage section:nth-child(2)
{
    color:#333;
    background: white;
    min-height: 100vh;
}


#fullpage section:nth-child(2) h1
{
    margin: 0;
    padding: 0;
    color:#333;
    text-align: center;
    padding: 20px 0px;
    font-family: 'Montserrat', sans-serif;
}

#fullpage section:nth-child(3)
{
    color:black;
    background: green;
    min-height: 100vh;
}
#fullpage section:nth-child(4)
{
    color:black;
    background: green;
    min-height: 100vh;
}

#fullpage section:nth-child(5)
{
    color:black;
    background: green;
    min-height: 100vh;
}

  <section> <div style="width:40px; height:40px; background-color:black;" onclick="bottomscroll()"> </section>
  <section><h1>text</h1></section>

  <section><h1>text</h1></section>

  <section><h1>text</h1></section>

  <section><h1>text</h1></section>

Answer 1

您的问题是，每次您在元素上循环以添加 display-none 类，然后删除 display -block 然后在循环之后将 display-block 添加到所需的元素，而不删除在循环内添加的 display-none。

代码应该是这样的:

function bottomscroll()
{
        ... 
        page.classList.remove("display-none"); /*added this*/
        page.classList.add("display-block");    
        ...
}

topscroll() 逻辑相同

这是一个只有一个功能的完整工作代码(在更正其他错误之后):

var nb = 1;


function bottomscroll() {
  if (nb != 4) {
    nb += 1;
    var page = document.querySelector("#fullpage section:nth-child(" + nb + ")");
    for (var i = 1; i < 4; i++) {
      var pagehidden = document.querySelector("#fullpage section:nth-child(" + i + ")");
      pagehidden.classList.add("display-none");
      pagehidden.classList.remove("display-block");
    }
    page.classList.remove("display-none");
    page.classList.add("display-block");
  }
}

.display-block {
  display: block;
}

.display-none {
  display: none;
}

#fullpage {
  overflow: hidden;
  margin: 0;
  padding: 0;
}

#fullpage section {
  min-height: 100%;
}

#fullpage section h4 {
  margin: 0;
  padding: 0;
}

#fullpage section:nth-child(1) {
  color: black;
  background: url(/img/fabian-grohs-597395-unsplash.jpg);
  background-repeat: no-repeat;
  background-size: cover;
  background-position: center;
  height: 100vh;
}

#fullpage section:nth-child(1) h1 {
  margin: 0;
  padding: 0;
  color: whitesmoke;
  text-align: center;
  padding: 70px;
  font-family: 'Montserrat', sans-serif;
  font-size: 40px;
}

#fullpage section:nth-child(1) p {
  text-align: center;
  color: white;
  font-size: 18px;
  width: 70%;
  margin: 0 auto;
  font-family: 'Inconsolata', monospace;
  position: relative;
}

#fullpage section:nth-child(2) {
  color: #333;
  background: white;
  min-height: 100vh;
}

#fullpage section:nth-child(2) h1 {
  margin: 0;
  padding: 0;
  color: #333;
  text-align: center;
  padding: 20px 0px;
  font-family: 'Montserrat', sans-serif;
}

#fullpage section:nth-child(3) {
  color: black;
  background: green;
  min-height: 100vh;
}

#fullpage section:nth-child(4) {
  color: black;
  background: green;
  min-height: 100vh;
}

#fullpage section:nth-child(5) {
  color: black;
  background: blue;
  min-height: 100vh;
}

<div style="width:40px; height:40px; background-color:black;" onclick="bottomscroll()"> </div>
<div id="fullpage">
  
  <section>
    <h1>text1</h1>
  </section>

  <section>
    <h1>text2</h1>
  </section>

  <section>
    <h1>text3</h1>
  </section>

  <section>
    <h1>text4</h1>
  </section>
</div>