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외부 xml파일을 로딩할 경우
charset이 utf-8이면 상관이 없지만, euc-kr일 경우 다음과 같이 설정을 해줘야 한다.

System.useCodePage = true;

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A Boolean value that tells Flash Player which code page to use to interpret external text files. When the property is set to false, Flash Player interprets external text files as Unicode. (These files must be encoded as Unicode when you save them.) When the property is set to true, Flash Player interprets external text files using the traditional code page of the operating system running the player. The default value of useCodePage is false.

Text that you load as an external file (using flash.display.Loader.load() or the flash.net.URLLoader, flash.net.URLStream, or XML class) must have been saved as Unicode in order for Flash Player to recognize it as Unicode. To encode external files as Unicode, save the files in an application that supports Unicode, such as Notepad on Windows 2000.

If you load external text files that are not Unicode-encoded, set useCodePage to true. Add the following as the first line of code in the first frame of the SWF file that is loading the data:

System.useCodePage = true;

When this code is present, Flash Player interprets external text using the traditional code page of the operating system running Flash Player. This is generally CP1252 for an English Windows operating system and Shift-JIS for a Japanese operating system. If you set useCodePage to true, Flash Player 6 and later treat text as Flash Player 5 does. (Flash Player 5 treated all text as if it were in the traditional code page of the operating system running the player.)

If you set useCodePage to true, remember that the traditional code page of the operating system running the player must include the characters used in your external text file in order to display your text. For example, if you load an external text file that contains Chinese characters, those characters cannot display on a system that uses the CP1252 code page because that code page does not include Chinese characters.

To ensure that users on all platforms can view external text files used in your SWF files, you should encode all external text files as Unicode and leave useCodePage set to false. This way, Flash Player 6 and later interprets the text as Unicode.

Implementation
    public static function get useCodePage():Boolean
    public function set useCodePage(value:Boolean):void