setUserData: key, data, handler(3)
The setUserData( )
method (in conjunction with the getUserData( )
method) provides a
facility for attaching application-specific information to DOM
nodes. By using distinct key values, it is possible to attach
multiple user objects to a single DOM node. The information to be
attached must conform to the DOMUserData
type and may include a data
handler object that implements the UserDataHandler
interface.