全选文本框案例

需求：用户点击全选，则下面复选框全部选择，取消全选则全部取消
屏幕截图 2023-10-31 165819.png
代码实现

<!DOCTYPE html>

<html>

<head lang="en">
  <meta charset="UTF-8">
  <title></title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    table {
      border-collapse: collapse;
      border-spacing: 0;
      border: 1px solid #c0c0c0;
      width: 500px;
      margin: 100px auto;
      text-align: center;
    }

    th {
      background-color: #09c;
      font: bold 16px "微软雅黑";
      color: #fff;
      height: 24px;
    }

    td {
      border: 1px solid #d0d0d0;
      color: #404060;
      padding: 10px;
    }

    .allCheck {
      width: 80px;
    }
  </style>
</head>

<body>
  <table>
    <tr>
      <th class="allCheck">
        <input type="checkbox" name="" id="checkAll"> <span class="all">全选</span>
      </th>
      <th>商品</th>
      <th>商家</th>
      <th>价格</th>
    </tr>
    <tr>
      <td>
        <input type="checkbox" name="check" class="ck">
      </td>
      <td>小米手机</td>
      <td>小米</td>
      <td>￥1999</td>
    </tr>
    <tr>
      <td>
        <input type="checkbox" name="check" class="ck">
      </td>
      <td>小米净水器</td>
      <td>小米</td>
      <td>￥4999</td>
    </tr>
    <tr>
      <td>
        <input type="checkbox" name="check" class="ck">
      </td>
      <td>小米电视</td>
      <td>小米</td>
      <td>￥5999</td>
    </tr>
  </table>
  <script>
    //获取元素
    const checkAll = document.querySelector('#checkAll')
    //获取小复选框
    const cks = document.querySelectorAll('.ck')
    //点击大复选框 注册事件
    checkAll.addEventListener('click', function () {
      //获取选中状态
      //遍历所有小复选框
      for (let i = 0; i < cks.length; i++) {
        cks[i].checked = checkAll.checked
      }
    })
    for (let i = 0; i < cks.length; i++) {
      cks[i].addEventListener('click', function () {
        const num = document.querySelectorAll('.ck:checked').length
        if (num === cks.length) {
          checkAll.checked = true
        }
      })
    }
  </script>
</body>

</html>