14.4. Reserved Words
Some reserved words are used by the ActionScript interpreter to denote specific built-in language features such as statements and operators. They are reserved for use by the interpreter, and we must avoid using them as identifiers in our code. Using a reserved word for a purpose other than its reserved internal purpose causes an error in most cases. The reserved words of ActionScript are listed in Table 14-1.
Table 14-1. ActionScript's Reserved Words
* Flash 4 reserved words deprecated in Flash 5.
You should also try to avoid using the keywords listed in Table 14-2. They are not part of ActionScript in Flash 5 but may become a part of the language in the future because they are slated for potential use by ECMA-262.
Table 14-2. Potential Future Reserved Words
In addition to the formally defined 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. For example:
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
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