operator
true if the last content of the element was one of the specified elements or #data, and
false otherwise. Replacing is with isnt reverses the result.
proper? content (of element-expression)? (is | isnt) (#DATA | element-name | content-identifier-list)
last content is an element test that evaluates to true in two cases:
#data was specified.
last content evaluates to false otherwise. Replacing is with isnt
will reverse these results.
When the keyword proper is specified, the last content is test ignores included
elements. If all the subelements of the referenced element have been included elements, and if there was no data
content in the element, the test fails.
Note that at the start of an element rule, there is no last content of that element,
so any test for it will fail.
The test last content is #data is true in a data-content rule only if the
data content is immediately preceded by either an external data entity reference or one or more processing
instructions, which are in turn preceded either by data content or by an external data entity reference. It
never applies to the content processed by the data-content rule.
The following is an example of a data-content rule that uses the last content is
test:
data-content output "%c" output " (again) " when last content is #data