带码一样为啥不能 全选和反选呢


<!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
      let all = document.querySelector('#checkAll')
      let cks = document.querySelector('.ck')
      let span = document.querySelector('span')
    //事件监听
    all.addEventListener('click', function() {
       //三个小东西在数组里面
      for(let i=0; i<cks.length; i++) {
        cks[i].checked = all .checked
      }
      if(all.checked ) {
        span.innerHTML='取消'}
        else{
          span.innerHTML='全选'
        }
      })
  </script>
</body>

</html>


 
<!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
      let all = document.querySelector('#checkAll')
      let cks = document.querySelectorAll('.ck')
      let span = document.querySelector('span')
    //事件监听
    all.addEventListener('click', function() {
       //三个小东西在数组里面
      for(let i=0; i<cks.length; i++) {
        cks[i].checked = all.checked
      }
      if(all.checked ) {
        span.innerHTML='取消'}
        else{
          span.innerHTML='全选'
        }
      })
  </script>
</body>
 
</html>

用这个试试，主要改动了这里

img