Adobe Extending Flash Professional CS5 - Manual (Page 450)

428 EXTENDING FLASH PROFESSIONAL
SymbolInstance object
Last updated 5/2/2011
Description
Property; a boolean value that sets the Visible property of an object to on (true) or off (false).
Example
The following example sets the visibility of the first item in the first frame of the first layer to false:
fl.getDocumentDOM().getTimeline().layers[0].frames[0].elements[0].visible = false;