ActionScript: The Definitive Guide

Chapter 6. Statements

We saw in earlier chapters how ActionScript stores and manipulates data. In this chapter we’ll learn how to do things with that data. We’ll give Flash instructions in the form of statements, or phrases of code that instruct the interpreter to perform some task.

To make something happen in Flash—whether stopping a sound, playing a movie, running a function, or looping some code—we use a statement. In fact, an ActionScript program can be defined as nothing more than a list of statements that tell the interpreter what we want Flash to do. Here, for example, is an entire ActionScript program, which consists of four statements and tells the interpreter to load a web page into the browser:

var protocol = "http";                                   // Statement 1
var domain = "www.moock.org";                            // Statement 2
var path = "webdesign/flash/";                           // Statement 3
getURL(protocol + "://" + domain + "/" + path);          // Statement 4

Scripting a movie with ActionScript is simply a matter of attaching statements to frames, movie clips, and buttons. This chapter explores the syntactic makeup of statements and lists the general statement categories. We’ll touch on all the ActionScript statements in this chapter, but some of the more important ones will be examined in detail in later chapters.

Types of Statements

Conceptually speaking, there are five core types of statements:

Statements that control the execution flow of a program

loops

conditionals

ifFrameLoaded

Statements that declare variables

var

set

Statements that declare, call, ...