The handler executes the following snippets in a restricted environment: _onstate-identifier (self, stateid, newstate) : The snippet is executed when the "state-identifier" attribute changes value; identifier may be any arbitrary string of one or more characters. self : Secure frame handle to the frame. stateid : String - identifier of the changed state. newstate : Mixed - new value of the "state-identifier" attribute. Note that if the value is not a string, boolean or a number, it'll be replaced with nil -- this a limitation enforced by the restricted environment.