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.

The ActionScript Statements

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play(); // Plays the current movie

gotoAndStop(5); // Sends the playhead to frame 5

startDrag("crosshair", true); // Makes the "crosshair" instance follow

// the mouse pointer

Function calls are also used with objects to invoke methods:

circle.getArea();

today.getDate();

Because movie clip instances are objects, we frequently use method invocation in our

scripts:

ball_mc.play()

intro_mc.gotoAndStop("end");

We’ll cover the use of functions in Chapter 9, and in Chapter 12 we’ll see how func-

tions can become object methods.

The return Statement

When we call a function, we can optionally pass it one or more values (parameters or

arguments) to manipulate during execution. Likewise, a function can send us back a

return value (a value that results from the execution of a function and is sent back to

the caller). Within the body of a function, we use the return statement to conclude

the function’s execution and optionally return a value. A return statement takes one

of the following forms:

return;

return expression;

The optional expression, if included, becomes the return value of the function. A

return statement without a return value exits the function and returns the value

undefined. All return statements exit the current function. Note that return state-

ments are ...