- Type: script code
This event is sent to a popup just before it is opened. This handler is usually used to dynamically set the contents when the user requests to display it. Returning
falsefrom this event handler prevents the popup from appearing.
- 该事件在 popup 打开之前传给它。它用于动态生成菜单项。如果返回 false 值，则 popup 将不会显示菜单项。