trueif the outermost element is the specified element, and
isntreverses the result.
doctype (is | isnt) namespace-modifier? (element-name | element-name-list)
doctype is tests whether the outermost element in the currently-active parse is 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
isnt will reverse these results.
You can specify an element name dynamically by using the identity operator (
~) followed by a