has-class() # boolean has-class(string|nodeset class_name [, nodeset context])
The function has-class() checks whether an element has a class attribute which
contains the given CSS class name. The search is case-insensitive. If no context parameter
is given, the current context node is used.
//*[has-class('myClass')] returns all elements which contain the class name
myClass in their class attributes.
has-class('myClass', /*) returns true if the document element contains myClass in
its class attribute, otherwise false.
Searching for multiple class names simultaneously (e.g. has-class('a b')) is not supported
and triggers a warning. Use an and or an or expression instead, e.g.
has-class('a') and has-class('b').
Searching an empty string is also not allowed and triggers a warning.