How Can I Add An Output Event to Menus Widgets by Coding?
Hello everone!
I want to build a Master like follwing pic.

Click the top menu which is parent menu of the leftside one, the leftside menu will change to appropriate sub items of the top.
I don`t want to build two Master or Mashup nested. It is better to solve by one Master.
Is there a mathod to add an output Event to Menus Widgets or create a Service for calling one or more sysytem Service as solution?

