如何遍歷和切換具有相同類/ VanillaJS的元素？

Question

我正在為搜索引擎做前端，並且有一個div，它會根據搜索結果重復很多次。 它們都需要具有截斷的文本並顯示更多/更少的按鈕。 我正在使用切換類來截斷文本。 我在下面編寫了代碼，但是，它僅適用於第一個div，但我不知道如何使其適用於所有div。 有人可以幫我解釋一下嗎？

我已經嘗試過使用for循環，但是我認為我做錯了

的HTML

<p class="result-box-description truncate">Lorem ipsum dolor sit amet, magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit...</p>
<span class="show">show more</span>
<p class="result-box-description truncate">Lorem ipsum dolor sit amet, magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit...</p>
<span class="show">show more</span>
<p class="result-box-description truncate">Lorem ipsum dolor sit amet, magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit...</p>
<span class="show">show more</span>

的CSS

p.result-box-description {
  @include tipography(14);
  color: #000;
  margin-top: 15px;
  margin-bottom: 15px;
  line-height: 1.2em;
  text-align: justify;

}
.truncate {
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  text-overflow: ellipsis;
}

的JavaScript

window.onload = function () {
  document.querySelector('.show').addEventListener('click', textToggle);
};

function textToggle() {
  const paragraphs = document.getElementsByClassName('result-box-description');
  const btn = document.querySelector('.show');

  for (var i = 0; i < paragraphs.length; i++) {
    paragraphs[i].classList.toggle('truncate');
  }

  if (paragraphs.classList.contains('truncate')) {
    btn.innerHTML = 'show more';
  } else {
    btn.innerHTML = 'show less';
  }
}

我只希望所有div都以相同的方式工作，因為我不知道實際的數字是多少。

Answer 1

以下是正確的結果嗎？

編輯：添加了切換邏輯

 window.onload = function() { Array.from(document.getElementsByClassName('show')).forEach(element => element.addEventListener('click', textToggle)); }; function textToggle(ev) { const paragraphs = document.getElementsByClassName('result-box-description'); const btns = document.getElementsByClassName('show'); var btn = ev.target; var para = ev.target.previousSibling.previousElementSibling; if (para.classList.contains("truncate")) { for (var i = 0; i < paragraphs.length; i++) { paragraphs[i].classList.add('truncate'); btns[i].innerHTML = 'show more'; } btn.innerHTML = "show less"; para.classList.remove("truncate"); } else { btn.innerHTML = "show more"; para.classList.add("truncate"); } } 

 p.result-box-description { @include tipography(14); color: #000; margin-top: 15px; margin-bottom: 15px; line-height: 1.2em; text-align: justify; } .truncate { display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; text-overflow: ellipsis; } 

 <p class="result-box-description truncate">Lorem ipsum dolor sit amet, magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit...</p> <span class="show">show more</span> <p class="result-box-description truncate">Lorem ipsum dolor sit amet, magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit...</p> <span class="show">show more</span> <p class="result-box-description truncate">Lorem ipsum dolor sit amet, magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptatelaboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit...</p> <span class="show">show more</span> 

Answer 2

您應該獲得所有“顯示”按鈕，並將事件附加到每個按鈕上。 您可以這樣做：

window.onload = function() {
  let shows = document.querySelectorAll('.show');
  shows.forEach((link) => { link.addEventListener('click', textToggle); });
};

function textToggle() {
  let paragraph = this.previousElementSibling;
  if (paragraph.classList.contains('truncate')) {
    paragraph.classList.remove('truncate');
    this.innerHTML = 'show less';
  } else {
    paragraph.classList.add('truncate');
    this.innerHTML = 'show more';
  }
}

我在textToggle中使用了previousElementSibling來指向要切換的段落。

這是一個Codepen： https ://codepen.io/kinospro/pen/zVPZaJ