Most ui components allow users to run custom logic on certain events. (ex. on initialize, on value change, on before save, ...)
These customizable events are available directly from the repository, as attributes.
The attributes support simple JavaScript syntax:

$ app.domain.function(eventSource);

The attributes require the value to start with '$', denoting that the used syntax will be JavaScript. (at the moment only JavaScript is supported)

Most of the time, the events will require access to the context of the event. (the object that is triggering the event, the screen, ...)
For that we introduced the following reserved keywords:

• self (deprecated) - the underlying dynObj of the triggering object
• oSelf (deprecated) - the underlying controller of the triggering object
• eventSource - the object on which the event is triggered
• eventOrigin - the container from where the current screen was launched