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.

Flash 4 Versus Flash 5 (and Later)

|

985

in Flash 5 and later. The old syntax is deprecated and no longer recommended.

Table C-2 shows equivalencies between Flash 4 and Flash 5 and later syntax when

addressing variables. See Table C-1 for other syntactical differences.

Local Variables in Flash 4–Style Subroutines

Although functions are the preferred mechanism for producing portable code mod-

ules, Flash 5 and Flash 6 still support Flash 4–style subroutines. In Flash 4, a subrou-

tine could be created by attaching a block of code to a frame with a label. Later, the

subroutine could be executed remotely via the Call action. But in Flash 4, any vari-

able declared in a subroutine was nonlocal and persisted for the lifetime of the time-

line on which it was defined. In Flash 5 and later, you can create local variables in

subroutines the same way we create them in functions—using the var statement.

However, variables defined with var in a subroutine are created as local variables

only when the subroutine is executed via the Call function. If the script on the sub-

routine frame is executed as a result of the playhead simply entering the frame, the

var statement declares a normal timeline nonlocal variable. Regardless, the more

modern functions and local function variables should be used instead ...