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.

Identifiers

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You should also try to avoid using the keywords listed in Table 15-2. They are not

reserved words for ActionScript in Flash MX, but they may become a part of the lan-

guage in the future, because they are slated for potential use by ECMA-262.

In addition to the formally defined reserved keywords, you should also

avoid using the names of built-in properties, methods, and objects as

identifiers in your code. Doing so overrides the default behavior of the

property, method, or object in question.

The following is a bad idea because the Date variable overrides the built-in construc-

tor of the same name:

Date = new Object(); // Oops! We just disabled the Date() constructor

Now we can no longer create Date objects:

var now = new Date( ); // Sets now to undefined

trace(now); // Displays the empty string, not the current time and date

Identifiers

All variables, functions, and object properties are named with identifiers. Action-

Script identifiers must be composed according to the following rules:

• Identifiers must start with a letter, underscore, or dollar sign (not a number).

• Identifiers cannot be identical to reserved words.

Table 15-1. ActionScript’s reserved words

add

*

*

Flash 4 reserved words that have been deprecated as of Flash 5.

delete ge

*

le

*

onClipEvent this

and

*

do gt

*