请参考以下代码：

JavaScriptAction javascipt_action = new JavaScriptAction(Action.create(doc, Action.e_TypeJavaScript));

javascipt_action.setScript("app.alert(\"Hello Foxit \");");

AdditionalAction aa = new AdditionalAction(doc);

aa.setAction(AdditionalAction.e_TriggerDocWillClose, javascipt_action);

aa.doJSAction(AdditionalAction.e_TriggerDocWillClose);