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.

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Chapter 6: Statements

Loops and Conditionals

We’ve already had several informal encounters with loops and conditionals.

Together, these two statement types account for the majority of complex flow in our

programs. Loops allow us to execute statement blocks repeatedly, and conditionals

allow us to execute statement blocks under only the specified circumstances. See

Chapters 7 and 8 for complete details.

Expression Statements

Although any expression can be used independently as a valid statement, if the

expression performs no action and we don’t do anything with the result, the exercise

is rather pointless:

"hi there"; // This doesn't do much

345 + 5; // Neither does this

Some expressions, however, have side effects that change the state of a system

through variable or property assignments or by physically altering the Flash environ-

ment. In this example, an expression changes the value of

x:

x = 345 + 5; // Much more useful

if-else if-else

if (expression) {

statements

} else if (expression) {

statements

} else {

statements

}

Executes one or more statements, based on a condi-

tion or a series of conditions

ifFrameLoaded

ifFrameLoaded (frame) {

statements

}

Executes specified code if a certain frame has loaded;

deprecated as of Flash 5

return

return;

return expression;

Exits and optionally returns a value ...