我可以覆盖 IE 中的默认消息(setMessage),但它在 FireFox 中不起作用
Window.addWindowClosingHandler(new Window.ClosingHandler() {
@Override
public void onWindowClosing(final Window.ClosingEvent closingEvent) {
//Working in IE, but not in FF
closingEvent.setMessage(mailingAddressExtractionMessages.mailingAddressExtraction_unsavedDataAlertMessage());
}
});