<thead>
=======

HTML 的 **`<thead>`** 元素定义了一组定义表格的列头的行。

尝试一下
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|  |  |
| --- | --- |
| 内容类别 (en-US) | 无。 |
| 允许内容 | 零或多个`<tr>`元素。 |
| 标签省略 | 开头的标签是强制的。如果`<thead>` 元素后直接跟 `<tbody>`或`<tfoot>`元素，结尾的标签可以被省略。 |
| Permitted parents | A `<table>` element. The `<thead>` must appear after any `<caption>` or `<colgroup>` element, even implicitly defined, but before any `<tbody>`, `<tfoot>` and `<tr>` element. |
| Permitted ARIA roles | Any |
| DOM interface | `HTMLTableSectionElement` (en-US) |

属性
--

This element includes the global attributes.

`align` 
已弃用

This enumerated attribute specifies how horizontal alignment of each cell content will be handled. Possible values are:

* `left`, aligning the content to the left of the cell
* `center`, centering the content in the cell
* `right`, aligning the content to the right of the cell
* `justify`, inserting spaces into the textual content so that the content is justified in the cell
* `char`, aligning the textual content on a special character with a minimal offset, defined by the `char` and `charoff` attributes 未实现 (查看 Firefox bug 2212).If this attribute is not set, the `left` value is assumed.

**备注：** Do not use this attribute as it is obsolete (not supported) in the latest standard.

* To achieve the same effect as the `left`, `center`, `right` or `justify` values, use the CSS `text-align` property on it.
* To achieve the same effect as the `char` value, in CSS3, you can use the value of the `char` as the value of the `text-align` property 未实现.

`bgcolor` 
非标准

This attribute defines the background color of each cell of the column. It is one of the 6-digit hexadecimal code as defined in sRGB, prefixed by a '#'. One of the sixteen predefined color strings may be used.

**备注：** Do not use this attribute, as it is non-standard and only implemented in some versions of Microsoft Internet Explorer: the `<thead>` element should be styled using CSS. To give a similar effect to the **bgcolor** attribute, use the CSS property `background-color`, on the relevant `<td>` (en-US) or `<th>` elements.

`char` 
已弃用

This attribute is used to set the character to align the cells in a column on. Typical values for this include a period (.) when attempting to align numbers or monetary values. If `align` is not set to `char`, this attribute is ignored.

**备注：** Do not use this attribute as it is obsolete (and not supported) in the latest standard. To achieve the same effect as the `char`, in CSS3, you can use the character set using the `char` attribute as the value of the `text-align` property 未实现.

`charoff` 
已弃用

This attribute is used to indicate the number of characters to offset the column data from the alignment characters specified by the **char** attribute.

**备注：** Do not use this attribute as it is obsolete (and not supported) in the latest standard.

`valign` 
已弃用

This attribute specifies the vertical alignment of the text within each row of cells of the table header. Possible values for this attribute are:

* `baseline`, which will put the text as close to the bottom of the cell as it is possible, but align it on the baseline of the characters instead of the bottom of them. If characters are all of the size, this has the same effect as `bottom`.
* `bottom`, which will put the text as close to the bottom of the cell as it is possible;
* `middle`, which will center the text in the cell;
* `top`, which will put the text as close to the top of the cell as it is possible.

**备注：** Do not use this attribute as it is obsolete (and not supported) in the latest standard: instead set the CSS `vertical-align` property on it.

示例
--

See `<table>` for examples on `<thead>`.

规范
--

| Specification |
| --- |
| HTML Standard # the-thead-element |

浏览器兼容性
------

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

参见
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* Other table-related HTML Elements: `<caption>`, `<col>`, `<colgroup>`, `<table>`, `<tbody>`, `<td>` (en-US), `<tfoot>`, `<th>`, `<tr>`;
* CSS properties and pseudo-classes that may be specially useful to style the `<thead>` element:
    + the `:nth-child` pseudo-class to set the alignment on the cells of the column;
    + the `text-align` property to align all cells content on the same character, like '.'.<