DOM节点学习

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【文档节点--DOM有哪些节点】

• 仔细看下面文档的html标签的不同

1.li标签没换行

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <ol><li>我是li1</li>
    <li>我是li2</li>
    <li>我是li3</li>
    <li id="li4">我是li4</li>
    <li>我是li5</li>
  </ol>
  <script>
    var ol = document.querySelector('ol');
    const li4 = document.getElementById('li4');
    console.log(ol.childNodes);
    console.log(li4.previousSibling) //#text
    console.log(li4.previousSibling.previousSibling); //li3
    console.log(li4.previousElementSibling); //li3
  </script>
</body>
</html>

• 其中的文本节点包括：文本，换行，空格等

2.li标签换行

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <ol>
    <li>我是li1</li>
    <li>我是li2</li>
    <li>我是li3</li>
    <li id="li4">我是li4</li>
    <li>我是li5</li>
  </ol>
  <script>
    var ol = document.querySelector('ol');
    const li4 = document.getElementById('li4');
    console.log(ol.childNodes);
    console.log(li4.previousSibling) //#text
    console.log(li4.previousSibling.previousSibling); //li3
    console.log(li4.previousElementSibling); //li3
  </script>
</body>
</html>

3.li标签换行且有注释

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <ol>
    <li>我是li1</li>
    <li>我是li2</li>
    <li>我是li3</li>
    <!-- 注释应该也是节点 -->
    <li id="li4">我是li4</li>
    <li>我是li5</li>
  </ol>
  <script>
    var ol = document.querySelector('ol');
    const li4 = document.getElementById('li4');
    console.log(ol.childNodes);
    console.log(li4.previousSibling) //#text
    console.log(li4.previousSibling.previousSibling); //li3
    console.log(li4.previousElementSibling); //li3
  </script>
</body>
</html>

• 其中的文本节点包括：文本，换行，空格等