DataTables lengthChange选项

DataTables是jQuery插件，可用于为网页的HTML表格添加互动和高级控件。这也使得表中的数据可以根据用户的需要进行搜索、排序和过滤。DataTable还暴露了一个强大的API，可以进一步用来修改数据的显示方式。

lengthChange选项用于指定是否显示用于改变每页行数的下拉菜单。这个下拉菜单只有在启用DataTable的分页功能时才会显示，因为禁用后会自动删除这个下拉菜单。真值会显示下拉菜单，假值会将其删除。

语法:

{ lengthChange: value }

选项值：该选项有一个上面提到的和下面描述的单一价值。

value。这是一个布尔值，用于指定是否显示改变行数的下拉菜单。默认值是true。

下面的例子说明了这个选项的使用。

例子1：这个例子通过删除下拉菜单，禁止改变每页的行数。

<html>
<head>
  <!-- jQuery -->
  <script type="text/javascript"
          src="https://code.jquery.com/jquery-3.5.1.js">
  </script>
  
  <!-- DataTables CSS -->
  <link rel="stylesheet"
        href=
"https://cdn.datatables.net/1.10.23/css/jquery.dataTables.min.css">
  
  <!-- DataTables JS -->
  <script src=
"https://cdn.datatables.net/1.10.23/js/jquery.dataTables.min.js">
  </script>
</head>
<body>
  <h1 style="color: green;">
    GeeksForGeeks
  </h1>
  <h3>DataTables lengthChange Option</h3>
  
  <!-- HTML table with student data -->
  <table id="tableID" class="display">
    <thead>
      <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>1</td>
        <td>Sam</td>
        <td>35</td>
      </tr>
      <tr>
        <td>2</td>
        <td>Sam</td>
        <td>30</td>
      </tr>
      <tr>
        <td>3</td>
        <td>Sameer</td>
        <td>45</td>
      </tr>
      <tr>
        <td>4</td>
        <td>Rob</td>
        <td>4</td>
      </tr>
      <tr>
        <td>5</td>
        <td>Robber</td>
        <td>68</td>
      </tr>
      <tr>
        <td>6</td>
        <td>Mikasa</td>
        <td>25</td>
      </tr>
      <tr>
        <td>7</td>
        <td>Eren</td>
        <td>23</td>
      </tr>
      <tr>
        <td>8</td>
        <td>Jean</td>
        <td>35</td>
      </tr>
      <tr>
        <td>9</td>
        <td>Walter</td>
        <td>65</td>
      </tr>
      <tr>
        <td>10</td>
        <td>Jessie</td>
        <td>28</td>
      </tr>
      <tr>
        <td>11</td>
        <td>Gabi</td>
        <td>20</td>
      </tr>
      <tr>
        <td>12</td>
        <td>Tim</td>
        <td>30</td>
      </tr>
      <tr>
        <td>13</td>
        <td>Max</td>
        <td>35</td>
      </tr>
    </tbody>
  </table>
  <script>
  
    // Initialize the DataTable
     $(document).ready(function () {$ ('#tableID').DataTable({
  
        // Disable the option to change
        // length in the DataTable
        lengthChange: false
      });
    }); 
  </script>
</body>
</html>

输出:

DataTables lengthChange选项

例子2：这个例子可以改变DataTable每页的行数。

<html>
<head>
  <!-- jQuery -->
  <script type="text/javascript"
          src="https://code.jquery.com/jquery-3.5.1.js">
  </script>
  
  <!-- DataTables CSS -->
  <link rel="stylesheet"
        href=
"https://cdn.datatables.net/1.10.23/css/jquery.dataTables.min.css">
  
  <!-- DataTables JS -->
  <script src=
"https://cdn.datatables.net/1.10.23/js/jquery.dataTables.min.js">
  </script>
</head>
<body>
  <h1 style="color: green;">
    GeeksForGeeks
  </h1>
  <h3>DataTables lengthChange Option</h3>
  
  <!-- HTML table with student data -->
  <table id="tableID" class="display">
    <thead>
      <tr>
        <th>ID</th>
        <th>Name</th>
        <th>Age</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>1</td>
        <td>Sam</td>
        <td>35</td>
      </tr>
      <tr>
        <td>2</td>
        <td>Sam</td>
        <td>30</td>
      </tr>
      <tr>
        <td>3</td>
        <td>Sameer</td>
        <td>45</td>
      </tr>
      <tr>
        <td>4</td>
        <td>Rob</td>
        <td>4</td>
      </tr>
      <tr>
        <td>5</td>
        <td>Robber</td>
        <td>68</td>
      </tr>
      <tr>
        <td>6</td>
        <td>Mikasa</td>
        <td>25</td>
      </tr>
      <tr>
        <td>7</td>
        <td>Eren</td>
        <td>23</td>
      </tr>
      <tr>
        <td>8</td>
        <td>Jean</td>
        <td>35</td>
      </tr>
      <tr>
        <td>9</td>
        <td>Walter</td>
        <td>65</td>
      </tr>
      <tr>
        <td>10</td>
        <td>Jessie</td>
        <td>28</td>
      </tr>
      <tr>
        <td>11</td>
        <td>Gabi</td>
        <td>20</td>
      </tr>
      <tr>
        <td>12</td>
        <td>Tim</td>
        <td>30</td>
      </tr>
      <tr>
        <td>13</td>
        <td>Max</td>
        <td>35</td>
      </tr>
    </tbody>
  </table>
  <script>
  
    // Initialize the DataTable
     $(document).ready(function () {$ ('#tableID').DataTable({
  
        // Enable the option to change
        // length in the DataTable
        lengthChange: true
      });
    }); 
  </script>
</body>
</html>

输出:

DataTables lengthChange选项