Chapter 12. Lists and Generated Content
In the realm of CSS layout, lists are an interesting case. The items
in a list are simply block
boxes, but with an extra bit that doesn't really
participate in the document layout hanging off to one side. With an
ordered list, that extra bit contains a series of increasing numbers
(or letters) that are calculated and mostly formatted by the user
agent, not the author. Taking a cue from the document structure, the
user agent generates the numbers and their basic presentation.
None of this content-generation could be described in CSS1
terms—and, therefore, it couldn't be
controlled—but
CSS2 introduced features that allow
list-item numbering to be described. As a result, CSS now lets you,
the author, define your own counting patterns and formats, and
associate those counters with any element, not
just ordered list items. Furthermore, this basic mechanism makes it
possible to insert other kinds of content, including text strings,
attribute values, or even external resources into a document. Thus,
it becomes possible to use CSS to insert link icons, editorial
symbols, and more into a design without having to create extra
markup.
To see how all these list options fit together,
we'll explore basic list styling before moving on to
examine the generation of content and counters.
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