The <thead> element in DITA tables serves a crucial role in defining the header section of a table. It is used to group and structure the header row(s) of a table, making it easier to identify and differentiate them from the data rows. The primary purpose of the <thead> element is to enhance table readability and comprehension by providing context and labels for the data columns.

When to Use <thead>

The <thead> element is typically used when you have a table that spans multiple pages or when you want to repeat the header row(s) at the top of each page for large tables. It ensures that the column headers are consistently displayed, making it easier for readers to understand the data, especially when scrolling through or printing lengthy tables. Additionally, it’s essential to use <thead> when your table includes complex structures like merged cells or columns with varying attributes.

Content of <thead>

The content of the <thead> element typically consists of one or more <row> elements, each containing the header cells (<entry> elements) that define the column labels or titles. These header cells provide a clear and concise description of the data in each column, aiding readers in understanding the information presented in the table. It is common practice to use <row> elements within <thead> to structure the header information effectively.

Example:

Here’s an example of how the <thead> element is used in a DITA table:

<table id="sample_table">
  <thead>
    <row>
      <entry>Product Name</strong></entry>
      <entry>Category</strong></entry>
      <entry>Price</strong></entry>
    </row>
  </thead>
  <tbody>
    <row>
      <entry>Product A</entry>
      <entry>Electronics</entry>
      <entry>$499.99</entry>
    </row>
    <row>
      <entry>Product B</entry>
      <entry>Home & Garden</entry>
      <entry>$299.95</entry>
    </row>
    <!-- Additional data rows -->
  </tbody>
</table>