Web Design in a Nutshell, 3rd Edition

Table Metadata

The first step in making a table accessible is to provide descriptions of the table using the caption element and summary attribute.

The caption element introduced earlier in this chapter provides a short descriptive title for the table. Visual browsers display the contents of the caption element above or below the table, as specified by an attribute or style property.

The summary attribute in the table element may provide a more lengthy description of the table. It is analogous to the alt attribute for images. Unlike the caption element, the value of the summary attribute is not rendered by visual browsers.

The summary may give visually impaired users a better understanding of the table’s contents and organization that sighted users could understand at a glance. This alleviates the need to read through several rows of data to decide whether a table will be useful. Although the summary is available for longer descriptions, authors are advised to keep summary descriptions clear and succinct and use them only when necessary.

The table in Figure 13-8 might be given the following caption and summary (note that summaries are more useful for tables that are more complex than this one).

<table summary="A comparison of major features for each planet in the solar system, relative to
 characteristics of the Earth.">
    <caption>Solar System Summary</caption>
    <tr>(table continues...)