Designing Web Navigation

A–Z INDEXES

An A–Z index is an alphabetical guide to topics, terms, and concepts found throughout a web site. Indexes generally supplement access to content and aren't a main point of entry. They provide a bottom-up view of a site's content and are the electronic version of the traditional back-of-the-book index. For sites with many repeat visitors, such as a company intranet, a site index can be particularly beneficial.

In a site index, each alphabetically arranged entry is linked to the page where that topic is discussed. Indexes can be quite long and are often divided into pages for each letter of the alphabet. A strip of letters is then linked, allowing users to jump to specific letter pages of the index.

Note that the body can also be a mix of links and text. Not all entries in an index are linked, particularly for "use" or "see" references. For example, if an entry for ping-pong points to table tennis via a see function, ping-pong may not be linked. Like this:

Ping-Pong

See: Table Tennis

The University of Auckland web site, for instance, has a simple A–Z index (www.auckland.ac.nz, Figure 3-21). In this case, the entire index is on one page. Clicking a letter in the alphabet jumps to the appropriate anchor. It is a simple, flat list of links with no cross references.

Figure 3-21. University of Auckland's simple index

By contrast, the BBC web site uses an extensive A–Z index^[49] with ...