Untyped Variables
All classes derive from the Object class that is known to flash programmers.
AS 2.0
In ActionScript 2.0, the lack of a type annotation meant that a variable would be of type Object.
var someObj:Object; var someObj;
AS 3.0
In ActionScript 3.0, however, an untyped varable is not the same as a variable of type Object. An untyped variable can hold undefined, while a variable of type Object cannot hold that value.
var someObj:*; var someObj;