复杂表头的粘性定位

Question

我正在尝试让一个复杂表头的粘性表头生效。它对于标准表格来说运作得很好。但是这个表格会在第一行停留而不是第二行，导致表头看起来“不协调”或者有点错落。我尝试将position属性设置为 sticky 放在 thead 上，但似乎没有任何效果。

以下是我的表格：

table {
  border: 1px solid black;
  font-size: 14px;
  margin: 10px 0;
  position: relative;
}

thead tr th {
  background-color: gray;
  position: sticky;
  top: -2px;
}

thead {
  border: 1px solid black;
  line-height: 1.25;
  overflow: hidden;
}

td {
  border: 1px solid black;
  line-height: 1.25;
  overflow: hidden;
  padding: 4px;
}

<table class='sticky-table'>
  <thead>
    <tr>
      <th rowspan="2">First column</th>
      <th colspan="3">Top of second column</th>
    </tr>
    <tr>
      <th>One</th>
      <th>Two</th>
      <th>Three</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
  </tbody>
</table>

- loctrice

Answer 1

我相信下面的js将解决这个问题。边框有些奇怪，但ths会正确地保持在那里。

var tableHeaderTop = document.querySelector('.sticky-table thead').getBoundingClientRect().top;
var ths = document.querySelectorAll('.sticky-table thead th')

for(var i = 0; i < ths.length; i++) {
  var th = ths[i];
  th.style.top = th.getBoundingClientRect().top - tableHeaderTop + "px";
}

table {
  border: 1px solid black;
  font-size: 14px;
  margin: 10px 0;
  position: relative;
}

thead tr th {
  background-color: gray;
  position: sticky;
  top: -2px;
}

thead {
  border: 1px solid black;
  line-height: 1.25;
  overflow: hidden;
}

td {
  border: 1px solid black;
  line-height: 1.25;
  overflow: hidden;
  padding: 4px;
}

<table class='sticky-table'>
  <thead>
    <tr>
      <th rowspan="2">First column</th>
      <th colspan="3">Top of second column</th>
    </tr>
    <tr>
      <th>One</th>
      <th>Two</th>
      <th>Three</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
  </tbody>
</table>

- Alex

Answer 2

我不喜欢这个解决方案，因为空格是“硬”编码的，但它按预期工作，我想，对吗？

table {
  border: 1px solid black;
  font-size: 14px;
  margin: 10px 0;
  position: relative;
}

thead tr th {
  background-color: gray;
  position: sticky;
  top: -2px;
}

.header {
  background-color: gray;
  position: sticky;
  top: 20px;
}

thead {
  border: 1px solid black;
  line-height: 1.25;
  overflow: hidden;
}

td {
  border: 1px solid black;
  line-height: 1.25;
  overflow: hidden;
  padding: 4px;
}

<table class='sticky-table'>
  <thead>
    <tr>
      <th rowspan="2">First column</th>
      <th colspan="3">Top of second column</th>
    </tr>
    <tr>
      <th class="header">One</th>
      <th class="header">Two</th>
      <th class="header">Three</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
    <tr>
      <td>First cell</td>
      <td>Second cell</td>
      <td>Third cell</td>
      <td>Fourth cell</td>
    </tr>
  </tbody>
</table>

- dns_nx

---

这绝对给了我一种思考的方法。但是我不能硬编码，因为样式必须适用于其他人创建的表格。 - loctrice

不幸的是，Firefox 仍然不支持粘性表头，我认为在所有浏览器都添加适当的支持之前，使用固定位置是唯一的解决方案。 - Roman Habibi

我只需要担心支持CSS属性的浏览器。如果不支持，那么它将像普通表格一样运行。 - loctrice