ActionScript for Flash MX: The Definitive Guide, Second Edition

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Chapter 9: Functions

is not reset (reinitialized) every time the function is called. As a general rule, function

properties should be used only to store information that pertains to the function.

More general information should be stored either in a class or as a global variable.

ActionScript functions can also have other functions attached to them, which can be

used to simulate Java-style static class methods. For example:

function SomeClass ( ) {

// Constructor code goes here.

}

SomeClass.staticMethod = function ( ) {

// Static method code goes here.

}

where SomeClass is the name of the class and staticMethod is the name of the static

method.

For examples of function methods, see the built-in Function.call( ) and Function.apply( )

methods in the Language Reference. These methods execute a function in the context

of a specified object. We’ll revisit static methods and the

prototype property in

Chapter 12.

Returning Functions from Functions

Finally, because function objects are data, they can be returned by functions. The fol-

lowing example shows a function, makeGotoHandler( ), that returns a nested func-

tion literal for use as the callback of a movie clip event handler. The function literal

sends the clip’s playhead to the frame specified by

frameNumber.

function makeGotoHandler (frameNumber) ...