ancestor ancestry-qualifier (is | isnt) element-name

An element test. An element can be opened more than once, so its "name" can occur more than once in a set of opened elements. As a consequence, a specific element is typically identified by a "relationship" to another element, as well as or instead of by its name. ancestor refers to any element containing the specified element at any level. This is a very broad parameter, so care should be taken in its use.

The test returns true if the element indicated has any ancestor with the specified element name, and false otherwise. Replacing is with isnt will reverse these results.

If no element qualifiers are present, the test always starts searching for ancestors starting with the parent of the current element.

Instead of specifying only a single element name, the test allows the programmer to specify a parenthesized list of element names separated by or (or |). The test succeeds if the reference element is identified by any of the names in this element name list.