operator
true if the parent of the element has the specified ancestor, and false otherwise.
Replacing is with isnt reverses the result.
preparent (of element-expression)? (is | isnt) namespace-modifier? (element-name | element-name-list)
preparent is tests whether the element stack of the parent of the current element of the
currently-active parse contains an instance of the element element-name, or one of the elements listed
in element-name-list. element-name-list is a parenthesized list of elements, separated by
|. Replacing is with isnt will reverse these results.
If element-expression is not specified, the test searches the element stack starting with the parent of the parent of the current element. If element-expression is specified, the search begins with the parent of the parent of the element specified by element-expression.
You can specify the name dynamically by using the identity operator (~) followed by a string expression: for example, to check for elements with a preparent of the same name as the current
element,
element #implied when preparent is ~(name of element) suppress