The ActionScript reference article from the English Wikipedia on 24-Jul-2004
(provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

ActionScript

People like you are child sponsors
ActionScript is an ECMAScript-based programming language used for controlling Macromedia Flash movies and applications. Since both ActionScript and JavaScript are based on the same ECMAScript syntax, fluency in one easily translates to the other. However, the client model is dramatically different: while JavaScript deals with windows, documents and forms, ActionScript deals with movie-clips, text fields and sounds.

ActionScript achieved something resembling it's current syntax (retroactively named ActionScript 1.0) in Flash 5, the first version of Flash to be thoroughly programmable. Flash 6 broadened the power of the programming environment by adding many more built-in functions and allowing more programatic control of movie elements. Flash 7 (MX 2004) introduced ActionScript 2.0, which adds strong typing and object-oriented features such as explicit class declarations, inheritance, interfaces, and encapsulation. ActionScript 1.0 and 2.0 share the same compiled form within Flash SWFs.

Features of the Flash ActionScript implementation that JavaScript programmers may find interesting:

ActionScript code is frequently written directly in the Flash authoring environment, which offers useful reference and powerful aids for syntax checking. In this case, the source code is saved along with the rest of the movie in a .fla file. It is also common for ActionScript code to be imported from external text files via #include statements. In this case, the external files are often given .as extensions, but this is not a universal convention.

Table of contents
1 Coding style
2 External links
3 See Also

Coding style

The following techniques are not required, but contribute towards more efficient, or at least more easily understandable code.

Naming

Naming involves capitalisation of code elements. Function names and variables should begin with a lower-case letter; objects should be capitalized. The first letter of each subsequent word should also be capitalised in both cases.

The Flash code editor features code completion only when variables are named according to a specific format. This involves appending the variable type to the end of the variable name.

Supported suffixes for code completion.
Object type Suffix string Example
String _str myString_str
Array _array myArray_array
MovieClip _mc myMovieClip_mc
TextField _txt myTextField_txt
Date _date myDate_date
Sound _sound mySound_sound
XML _xml myXML_xml
Color _color myColor_color

Commenting code

Commenting code is always recommended. Comments should document the decisions made while building the code, telling the story of what it attempts to do. A future developer should be able to pickup the logic of the code with the assistance of the comments.

var clicks = 0;    // This is a simple comment


/*

This is a multiline comment.

.....

.....

*/
Some common methods for indicating important comments are:

// :TODO: more work to be done here

// :BUG: [bugid] this is a known issue

// :KLUDGE: this bit isn't very elegant

// :TRICKY: lots of interactions, think twice before modifying

Timeline layout

Scoping variables

_parent.myVar.blah = 100;  // Use relative addressing like this

_root.myClip = 200;        // Avoid absolute addressing as much as possible

_global.myVar = 300;       // _global variables are available to all movies within the player

Keep actions together

Avoid attaching code to Movie Clips or buttons

Attempt to write event code on a frame rather than on the object itself, unless it is purely a function call.

// CODE ON BUTTON - Not Recommended

on (release) {

    play();

}


// CODE ON FRAME - Recommended

myButton.onRelease = function() {

    play();

}

Source

Information above is summarised from Macromedia's ActionScript Coding Standards. For a more complete explanation, please see the full document.

http://www.macromedia.com/devnet/mx/flash/whitepapers/actionscript_standards.pdf

External links

See Also