class and all methods
markItem( index )
Mark the item specified by the index as current activated.
index : Object
markFirstDisplayed( beforeMark )
Marks the first visible item or the one whose
aria-selectedattribute is set to
true. The latter has priority over the former.
beforeMark : Object
function to be executed just before marking. Used in cases when any preparatory cleanup (like unmarking all items) would simultaneously destroy the information that is needed to determine the focused item.