The Viewer object represents a Composition, Layer, or Footage panel.
This maximizes the active viewer panel, and displays its type if it contains a composition:
var activeViewer = app.activeViewer;
activeViewer.maximized = true;
if (activeViewer.type == ViewerType.VIEWER_COMPOSITION)
alert(Composition panel is active.");
Attribute Reference Description
type “Viewer type attribute” The type of content in the viewer.
active “Viewer active attribute” When true, the viewer is focused.
maximized “Viewer maximized attribute” When true, the viewer is at its maximized size.
Method Reference Description
setActive() “Viewer setActive() method” Moves the viewer to front and places focus on it.