built-in shelf
#content represents the section of a markup source contained within the markup-region-event that triggered the rule. In an element rule, for example, #content is
the the markup source including all content and markup events contained within the element. No other
rules are triggered while #content is being processed, however, #content can be consumed by
another do markup-parse action, which would then invoke all the rules triggered by the markup events
contained within #content.
#content can only be used in the body of the following rules and actions:
do markup-parse
do sgml-parse
do xml-parse
data-content
element
invalid-data
marked-section cdata
marked-section ignore
marked-section rcdata
markup-comment
It is not available in the rule guards, nor in any function called by a rule. It can, however, be passed from
one of the rules listed above to a function as a value markup source argument.