Question

我坚持使用这种简单的JS DOM操作。以下是我的HTML标记。我正在尝试使用JS动态生成单个列表项。

我的问题：每个Span标签都应包含对象数组中的单个项目，但在我的情况下，一个span标签将包含所有元素。我如何使它工作？我知道这一定很简单，但是我无法弄清楚我在哪里错了？

HTML代码：

<ul class="collection" id="web-book-list">
            <li class="collection-item">
              <span class="flow-text">item 1</span>
              <a href="#!" class="secondary-content"
                ><i class="small material-icons black-text">visibility</i></a
              >
              <a href="#!" class="secondary-content"
                ><i class="small material-icons red-text">delete_forever</i></a
              >
            </li>
            <li class="collection-item">
              <span class="flow-text">item 2</span>
              <a href="#!" class="secondary-content"
                ><i class="small material-icons black-text">visibility</i></a
              >
              <a href="#!" class="secondary-content"
                ><i class="small material-icons red-text">delete_forever</i></a
              >
            </li>
        </ul>

JS代码：

let bookList = document.getElementById("web-book-list");
  // Create element
  let li = document.createElement("li");
  let span = document.createElement("span");
  let linkA = document.createElement("a");
  let linkB = document.createElement("a");
  let visible = document.createElement("i");
  let deleteBtn = document.createElement("i");

  // Add classes to elements
  li.className = "collection-item";
  span.className = "flow-text";
  linkA.className = "secondary-content";
  linkB.className = "secondary-content";
  visible.className = "small material-icons black-text";
  deleteBtn.className = "small material-icons red-text";

  // create text nodes
  visible.appendChild(document.createTextNode("visibility"));
  deleteBtn.appendChild(document.createTextNode("delete_forever"));

  linkA.appendChild(visible);
  linkB.appendChild(deleteBtn);

  //Loop through the webBooks

  for (let i = 0; i < webBooks.length; i++) {
    console.log(webBooks[i]);
    span.innerHTML += webBooks[i].name; // Problem is here!

    li.appendChild(span);
    li.appendChild(linkA);
    li.appendChild(linkB);
    bookList.appendChild(li);
  }
  console.log(bookList);

Answer 1

您需要为循环中的每本书创建一个span元素。您还需要创建li和链接。当您使用appendChild附加文档中其他位置已经存在的元素时，它会被移动，而不是被复制。

由于您是在元素等上设置类，因此为循环的每次迭代创建单个类的最简单方法是使用cloneNode：

let bookList = document.getElementById("web-book-list");
// Create element
let li = document.createElement("li");
let span;                                    // *** No need to create one here
let linkA = document.createElement("a");
let linkB = document.createElement("a");

// ...

for (let i = 0; i < webBooks.length; i++) {
  console.log(webBooks[i]);
  const thisSpan = span.cloneNode(true);     // ***
  thisSpan.innerHTML = webBooks[i].name;     // *** No need for += since we're creating a new span

  const thisLi = li.clone(true);             // ***
  thisLi.appendChild(thisSpan);              // ***
  thisLi.appendChild(linkA.cloneNode(true)); // ***
  thisLi.appendChild(linkB.cloneNode(true)); // ***
  bookList.appendChild(thisLi);              // ***
}

我还建议您不要在此处将文本视为HTML：

thisSpan.innerHTML = webBooks[i].name;

如果该名称中包含<（甚至包含恶意脚本内容），将其视为HTML就是一个问题。相反：

thisSpan.appendChild(document.createTextNode(webBooks[i].name));

Answer 2

删除+=并追加bookList.appendChild(li.cloneNode(true));

var bookList = document.getElementById("web-book-list");
  // Create element
  var li = document.createElement("li");
  var span = document.createElement("span");
  var linkA = document.createElement("a");
  var linkB = document.createElement("a");
  var visible = document.createElement("i");
  var deleteBtn = document.createElement("i");

  // Add classes to elements
  li.className = "collection-item";
  span.className = "flow-text";
  linkA.className = "secondary-content";
  linkB.className = "secondary-content";
  linkA.href = "#0";
  linkB.href = "#0";
  visible.className = "small material-icons black-text";
  deleteBtn.className = "small material-icons red-text";

  // create text nodes
  visible.appendChild(document.createTextNode("visibility "));
  deleteBtn.appendChild(document.createTextNode("delete_forever"));

  linkA.appendChild(visible);
  linkB.appendChild(deleteBtn);

  //Loop through the webBooks

  for (let i = 0; i < 10; i++) {
    span.innerHTML = "test"+i+ " "; // Problem is here!

    li.appendChild(span);
    li.appendChild(linkA);
    li.appendChild(linkB);
    bookList.appendChild(li.cloneNode(true));
  }

<ul class="collection" id="web-book-list">
            <li class="collection-item">
              <span class="flow-text">item 1</span>
              <a href="#!" class="secondary-content"
                ><i class="small material-icons black-text">visibility</i></a
              >
              <a href="#!" class="secondary-content"
                ><i class="small material-icons red-text">delete_forever</i></a
              >
            </li>
            <li class="collection-item">
              <span class="flow-text">item 2</span>
              <a href="#!" class="secondary-content"
                ><i class="small material-icons black-text">visibility</i></a
              >
              <a href="#!" class="secondary-content"
                ><i class="small material-icons red-text">delete_forever</i></a
              >
            </li>
        </ul>

也不要忘记href

linkA.href = "#0";
linkB.href = "#0";

卡在JS DOM操作中

2 个答案: