我可以在IE中覆盖默认消息( 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());
}
});