var nonelbll = null var commandd = null; var swapper = function(ov, old, running) { commandd.setVisible(running); nonelbll.setVisible(!running); }; var runnerVp = null; function replaced() { runnerVp = base.getObservable("hasCommand"); runnerVp["addListener(javafx.beans.value.ChangeListener)"](swapper); nonelbll = nonelbl; commandd = command; if (typeof runnerVp == "boolean") { swapper(null, null, runnerVp.getValue()); } else { swapper(null, null, false); } }