Struct Th 

pub struct Th;

The <th> element - defines a header cell in a table.

Purpose

The <th> element represents a header cell in a table. It labels a row or column of data cells, providing context for the information in the table. Header cells are typically rendered with bold, centered text by default and are crucial for table accessibility.

Content Categories

• None (only valid within <tr>)

Permitted Content Model

• Flow content (excluding header, footer, sectioning content, and heading content)

Common Use Cases

• Labeling table columns
• Labeling table rows
• Creating multi-level headers with rowspan/colspan
• Providing context for data cells
• Improving table accessibility for screen readers

Key Attributes

• scope: Specifies cells the header relates to (“row”, “col”, “rowgroup”, “colgroup”)
• colspan: Number of columns the header spans
• rowspan: Number of rows the header spans
• headers: Space-separated list of other header cell IDs
• abbr: Abbreviated description of the header

Example

<!-- Column headers -->
<table>
  <thead>
    <tr>
      <th scope="col">Name</th>
      <th scope="col">Email</th>
      <th scope="col">Role</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Alice</td>
      <td>alice@example.com</td>
      <td>Developer</td>
    </tr>
  </tbody>
</table>

<!-- Row headers -->
<table>
  <tbody>
    <tr>
      <th scope="row">Product A</th>
      <td>$99</td>
      <td>In Stock</td>
    </tr>
    <tr>
      <th scope="row">Product B</th>
      <td>$149</td>
      <td>Out of Stock</td>
    </tr>
  </tbody>
</table>

<!-- Multi-level headers -->
<table>
  <thead>
    <tr>
      <th rowspan="2" scope="col">Name</th>
      <th colspan="2" scope="colgroup">Scores</th>
    </tr>
    <tr>
      <th scope="col">Math</th>
      <th scope="col">Science</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <th scope="row">Alice</th>
      <td>95</td>
      <td>92</td>
    </tr>
  </tbody>
</table>

<!-- Headers with abbreviations -->
<table>
  <thead>
    <tr>
      <th scope="col" abbr="Temp">Temperature (°F)</th>
      <th scope="col" abbr="Humid">Humidity (%)</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>72</td>
      <td>65</td>
    </tr>
  </tbody>
</table>

Accessibility

• Always use scope attribute to clarify what the header labels
• Use “col” for column headers, “row” for row headers
• Use “colgroup” or “rowgroup” for headers spanning groups
• Provide abbr for long header text to aid screen readers
• Ensure header text is concise and descriptive

WHATWG Specification

• 4.9.10 The th element

Trait Implementations

impl HtmlElement for Th

const TAG: &'static str = "th"

The HTML tag name (e.g., “div”, “span”, “img”).

const VOID: bool = false

Whether this is a void element (self-closing, no children allowed).

impl<T: FlowContent> CanContain<T> for Th

impl CanContain<Text> for Th

impl CanContain<Th> for Tr