HTML and CSS Reference
In-Depth Information
10.3. Advanced Table Tags
While it is possible to build a simple table quickly, complex tables with
varying border styles, running headers and footers, and column-based
layout were not easily constructed from the old HTML 3.2 table mod-
el. Microsoft rectified this inadequacy somewhat by adding a number of
table-layout controls to Internet Explorer version 3.0. These very useful
extensions found their way into the HTML 4 standard and subsequently
into XHTML. They provide row-based grouping and running headers and
footers, along with column-based layout features.
10.3.1. Defining Table Sections
Within tables, all rows are created equal. In real tables, some rows
are more equal than others. And most tables have header and footer
rows that repeat from page to page. In large tables, adjacent rows are
grouped and delineated with different rule lines to make the tables easier
to read and understand. HTML 4 and XHTML support all of these features
with the
<thead>, <tfoot>
, and
<tbody>
tags.
10.3.2. The <thead> Tag
Use the
<thead>
tag to define a set of table header rows. The
<thead>
tag
may appear only once per table and is placed at the beginning, just after
the
<table>
tag. Within the
<thead>
tag, you may place one or more
<tr>
tags, defining the rows within the table header. If given the opportun-
ity, the HTML 4/XHTML-compliant browser replicates these heading rows
when the table is printed or displayed in multiple sections. Thereafter,
it repeats these headings on each printed page if the table appears on
more than one page.
