21.1.3.4 headers

This element specifies the list of header cells, as specified by children header elements, that provide header information associated with the current table cell. Each header cell shall specify a unique identifier, as specified by the use of the attribute id on the header cell tc element. This element is typically used to gather header information about data and sub header cells.

If this element is omitted or there exists no children header element, no header cell shall be associated with the given table cell.

[Example: Consider the following 3 x 3 table with four header cells with values A, B, C, and D and four data cells with values x1, x2, y1, and y2:

A

B

C

x1

x2

D y1 y2 Each of the data cells is associated with two header cells and can be represented in DrawingML as follows:

<a:tbl>
  …
  <a:tr>
    …
    <a:tc >
      …
    </a:tc>
    <a:tc id="HeaderA">
      …
      <a:p>
        <a:r>
          <a:t>A</a:t>
        </a:r>
      </a:p>
    </a:tc>
    …
  </a:tr>
  <a:tr>
    …
    <a:tc id="HeaderC">
      …
      <a:p>
        <a:r>
          <a:t>C</a:t>
        </a:r>
      </a:p>
    </a:tc>
    <a:tc>
      <a:p>
        <a:r>
          <a:t>x1</a:t>
        </a:r>
      </a:p>
      <a:tcPr>
        …
        <a:headers>
          <a:header val="HeaderA" />
          <a:header val="HeaderC" />
        </a:headers>
        …
      </a:tcPr>
    </a:tc>
    …
  </a:tr>
</a:tbl>

The headers element specifies the list of header cells associated with the table cell that has a value of x1. In this example x1 is associated with headers that have an id of HeaderA and HeaderC. end example]

[Note: The W3C XML Schema definition of this element’s content model (CT_Headers) is located in A.4.1. end note]