MACROMEDIA FLASH MX 2004 - ACTIONSCRIPT Reference Manual page 52

You can also define a function by creating a function literal—an unnamed function that is
declared in an expression instead of in a statement. You can use a function literal to define a
function, return its value, and assign it to a variable in one expression, as shown in the
following example:
area = (function() {return Math.PI * radius *radius;})(5);
When a function is redefined, the new definition replaces the old definition.
Passing parameters to a function
Parameters are the elements on which a function executes its code. (In this manual, the terms
parameter and argument are interchangeable.) For example, the following function takes the
parameters
initials
function fillOutScorecard(initials, finalScore) {
scorecard.display = initials;
scorecard.score = finalScore;
}
When the function is called, the required parameters must be passed to the function. The
function substitutes the passed values for the parameters in the function definition. In this
example,
scorecard
fields in the instance. The following function call assigns the value
and the value
45000
fillOutScorecard("JEB", 45000);
The parameter
initials
exists while the function is called and ceases to exist when the function exits. If you omit
parameters during a function call, the omitted parameters are passed as
extra parameters in a function call that are not required by the function declaration, they
are ignored.
Using variables in a function
Local variables are valuable tools for organizing code and making it easy to understand. When a
function uses local variables, it can hide its variables from all other scripts in the SWF file; local
variables are scoped to the body of the function and ceases to exist when the function exits. Any
parameters passed to a function are also treated as local variables.
You can also use global and regular variables in a function. However, if you modify global or
regular variables, it is good practice to use script comments to document these modifications.
52 Chapter 2: ActionScript Basics
and :
finalScore
is the instance name of a movie clip;
to the variable :
score
in the function
fillOutScorecard()
and are input text
display score
to the variable
"JEB"
is similar to a local variable; it
undefined
display
. If you provide