You can create the following types of components in ActionScript:
User-interface components User-interface components contain both processing logic and visual elements. These components usually extend the Flex component hierarchy. You can extend from the UIObject and UIComponent classes, or any of the Flex components, such as Button, ComboBox, or DataGrid. Your custom ActionScript component inherits all of the public methods and properties of its parent class.
Nonvisual components Nonvisual components define no visual elements. By definition, a nonvisual component is an ActionScript class that does not extend the UIObject, UIComponent, or MovieClip classes. Using nonvisual components can provide greater efficiency at runtime.