Question

编辑：我用答案返回js fiddle，但仍然返回未定义的函数。

我正在努力找出为什么我的函数返回未定义的原因。我的html：

<div class="slideshow">
            <div class="slide">  
                <div class="work-info col-3">
                    <div class="block-orange">
                        <h3>Work</h3>
                        <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Nisi ipsum iure esse nemo facere ea, iste deserunt odit provident labore exercitationem nihil, laborum, sit vel nostrum illo ducimus possimus dolorum.</p>
                    </div>
                </div>
            </div>
            <div class="slide">
            </div>
            <div class="slide">
            </div>
            <div class="slide">
            </div>

            <div class="dot-cont">
              <div class="dot" onclick="clickChangeSlide(0)"></div>
              <div class="dot" onclick="clickChangeSlide(1)"></div>
              <div class="dot" onclick="clickChangeSlide(2)"></div>
              <div class="dot" onclick="clickChangeSlide(3)"></div>
            </div>
            <button class="arrow-button left-arrow" onclick="clickChangeSlide(i-1)">&#60;</button>
            <button class="arrow-button right-arrow" onclick="clickChangeSlide(i+1)">&#62;</button>      
    </div>

该js正在页面底部加载。 JS：

document.addEventListener("DOMContentLoaded", function(event) {
  let i = -1;
  let time = 5000;
  let slideTimer;
  let slides = document.getElementsByClassName('slide');
  let slideDots = document.getElementsByClassName('dot');

  function clickChangeSlide(n){
    clearTimeout(slideTimer);
    changeSlide(n, true);
  }

  function changeSlide(n = i, manual = false){

    for(let j = 0; j < slides.length; j++){
      if(j == i) {
        slides[j].classList.add('prev-slide');
        slides[j].classList.remove('active-slide');
        slideDots[j].classList.remove('active-dot');
        continue; 
      }
      slideDots[j].classList.remove('active-dot');
      slides[j].classList.remove('prev-slide'); 
      slides[j].classList.remove('active-slide');
    }
    if(manual){
      if(n < 0) i = slides.length - 1
      else if(n > slides.length - 1) i = 0
      else i = n
    }else i = i < slides.length - 1 ? i+1 : 0;

    slides[i].classList.add('active-slide');
    slideDots[i].classList.add('active-dot');

    slideTimer = setTimeout(changeSlide, time);
  }

  window.onload = changeSlide();
});

我试图删除DomcontentLoaded，因为我认为这可能会影响到它，但没有成功。当我单击按钮时，不会触发ClickChangeSlide。有任何想法吗？

Answer 1

您正在回调中定义<div id="details-container" class="style-scope ytd-channel-about-metadata-renderer"> <yt-formatted-string class="subheadline style-scope ytd-channel-about-metadata-renderer">Details</yt-formatted-string> <table class="style-scope ytd-channel-about-metadata-renderer"> <tbody class="style-scope ytd-channel-about-metadata-renderer"> <tr class="style-scope ytd-channel-about-metadata-renderer"> <td class="label style-scope ytd-channel-about-metadata-renderer"> <yt-formatted-string class="style-scope ytd-channel-about-metadata-renderer"></yt-formatted-string> </td> <td class="style-scope ytd-channel-about-metadata-renderer"> <ytd-button-renderer align-by-text="" class="style-scope ytd-channel-about-metadata-renderer" button-renderer=""></ytd-button-renderer> <div id="captcha-container" class="style-scope ytd-channel-about-metadata-renderer"></div> <div id="email-container" class="style-scope ytd-channel-about-metadata-renderer"></div> <a id="email" target="_blank" class="style-scope ytd-channel-about-metadata-renderer" href="mailto:undefined" hidden=""></a> </td> </tr> <tr class="style-scope ytd-channel-about-metadata-renderer"> <td class="label style-scope ytd-channel-about-metadata-renderer"> <yt-formatted-string class="style-scope ytd-channel-about-metadata-renderer"><span class="deemphasize style-scope yt-formatted-string"> Location: </span></yt-formatted-string> </td> <td class="style-scope ytd-channel-about-metadata-renderer"> <yt-formatted-string class="style-scope ytd-channel-about-metadata-renderer">YourCountry</yt-formatted-string> </td> </tr> </tbody> </table> </div>，因此在整个文档中都不存在它的作用域。

您必须在回调之外定义它，例如：

clickChangeSlide()

Answer 2

您的DOM尝试访问DOM构建时不可用的功能，onclick=clickChangeSlide(0)...对此负责。将changeSlide(...)和clickChangeSlide(...)这两个函数放在您实际的DOMContentLoaded事件侦听器的外部，以便在DOM构建期间访问这些函数。

它看起来像这样：

<div class="slideshow">
    <div class="slide">  
        <div class="work-info col-3">
            <div class="block-orange">
                <h3>Work</h3>
                <p>Lorem ipsum...</p>
            </div>
        </div>
    </div>
    <div class="slide"></div>
    <div class="slide"></div>
    <div class="slide"></div>
    <div class="dot-cont">
         <div class="dot" onclick="clickChangeSlide(0)"></div>
         <div class="dot" onclick="clickChangeSlide(1)"></div>
         <div class="dot" onclick="clickChangeSlide(2)"></div>
         <div class="dot" onclick="clickChangeSlide(3)"></div>
    </div>
    <button class="arrow-button left-arrow" onclick="clickChangeSlide(i-1)">&#60;</button>
    <button class="arrow-button right-arrow" onclick="clickChangeSlide(i+1)">&#62;</button>
</div>

您的JavaScript代码应如下所示：

let i = -1;
var slideTimer;
let time = 5000;
let slides = document.getElementsByClassName('slide');
let slideDots = document.getElementsByClassName('dot');

function changeSlide(n = i, manual = false) {
    for (let j = 0; j < slides.length; j++) {
        if (j == i) {
            slides[j].classList.add('prev-slide');
            slides[j].classList.remove('active-slide');
            slideDots[j].classList.remove('active-dot');
            continue; 
        }
        slideDots[j].classList.remove('active-dot');
        slides[j].classList.remove('prev-slide'); 
        slides[j].classList.remove('active-slide');
    }
    if (manual) {
        if(n < 0) i = slides.length - 1
        else if(n > slides.length - 1) i = 0
        else i = n
    } else i = i < slides.length - 1 ? i+1 : 0;

    slides[i].classList.add('active-slide');
    slideDots[i].classList.add('active-dot');

    slideTimer = setTimeout(changeSlide, time);
};

function clickChangeSlide(n) {
    clearTimeout(slideTimer);
    changeSlide(n, true);
};

document.addEventListener("DOMContentLoaded", function(event) {
    window.onload = changeSlide();
});

您还必须更改变量i, slides, slideDots, ...的范围，因为在声明变量之前访问changeSlide。使用<script src="javascript.js"></script>将您的javascript代码加载到html代码的顶部，否则您的DOM无法将任何函数初始化为div元素的onload函数。

点击事件未定义Javascript函数

2 个答案: