ActionScript for Flash MX: The Definitive Guide, Second Edition

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

Function Availability and Life Span

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Function Availability

Custom program functions (the functions we create in our code) are directly accessi-

ble for invocation only from:

• Code attached to the timeline of the movie clip that bears the function declara-

tion

• Code in a Flash 5–style onClipEvent( ) handler on the movie clip that bears the

function declaration

• Code in a Flash 5–style on( ) event handler on a button on the timeline of the

movie clip that bears the function declaration

By “directly accessible,” we mean that the function can be invoked simply by name,

without reference to a movie clip or object, like this:

myFunction();

Functions are also indirectly accessible (i.e., remotely accessible), using dot syntax,

from any point in a movie. As when referring to variables remotely, we must include

the path to the movie clip that contains the function, such as:

myClip.myOtherClip.myFunction();

_parent.myFunction();

_root.myFunction();

So, suppose a clip instance named rectangle on the main timeline contains a func-

tion named area( ). We can invoke area( ) from anywhere in our movie, using an

absolute path to

rectangle, like this:

_root.rectangle.area();

To reference a function from a remote movie clip timeline, we follow the same rules

used when referring to remote variables, as