Editing ActionScript (section)

==Syntax==
ActionScript code is [[free-form language|free form]] and thus may be created with whichever amount or style of whitespace that the author desires. The basic syntax is derived from [[ECMAScript]].

===ActionScript 2.0===
The following code, which works in any compliant player, creates a text field at depth 0, at position (0, 0) on the screen (measured in [[pixel]]s), that is 100 pixels wide and high. Then the <code>text</code> parameter is set to the "{{Mono|Hello, world}}" [[String (computer science)|string]], and it is automatically displayed in the player:
<syntaxhighlight lang="actionscript">
createTextField("greet", 0, 0, 0, 100, 100);
greet.text = "Hello, world";
</syntaxhighlight>
When writing external ActionScript 2.0 class files the above example could be written in a file named {{Mono|Greeter.as}} as following.
<syntaxhighlight lang="actionscript">
class com.example.Greeter extends MovieClip
{
    public function Greeter()
    {
        var txtHello: TextField = this.createTextField("txtHello", 0, 0, 0, 100, 100);
        txtHello.text = "Hello, world";
    }
}
</syntaxhighlight>

===ActionScript 3.0===
ActionScript 3.0 has a similar syntax to ActionScript 2.0, but a different set of APIs for creating objects. Compare the script below to the previous ActionScript 2.0 version:
<syntaxhighlight lang="actionscript3">
var txtHello: TextField = new TextField();
txtHello.text = "Hello World";
this.addChild(txtHello);
</syntaxhighlight>

Minimal ActionScript 3.0 programs may be somewhat larger and more complicated due to the increased separation of the programming language and the Flash [[integrated development environment]] (IDE).

Presume the following file to be {{Mono|Greeter.as}}:
<syntaxhighlight lang="actionscript3">
package com.example
{
    import flash.text.TextField;
    import flash.display.Sprite;

    public class Greeter extends Sprite
    {
        public function Greeter()
        {
            var txtHello: TextField = new TextField();
            txtHello.text = "Hello World";
            this.addChild(txtHello);
        }
    }
}
</syntaxhighlight>
{{See also|Sprite (computer graphics)}}

ActionScript 3 can also be used in [[MXML]] files when using [[Apache Flex|Apache's Flex]] framework:
<syntaxhighlight lang="mxml">
<?xml version="1.0" encoding="utf-8"?>
<s:Application
         xmlns:fx="http://ns.adobe.com/mxml/2009"
	     xmlns:s="library://ns.adobe.com/flex/mx/polysylabi"
	     xmlns:mx="library://ns.adobe.com/flex/mx"
         layout="vertical"
         creationComplete="initApp()">

    <fx:Script>
        <![CDATA[
            public function initApp(): void {
               // Prints our "Hello, world!" message into title
               title.text = "Hello, World!";
            }
        ]]>
    </fx:Script>

    <s:Label id="title" fontSize="54" fontStyle="bold" />
</s:Application>
</syntaxhighlight>