<?xml version="1.0" encoding="utf-8"?>
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" height="150">
    <mx:Script>
    <![CDATA[
        import flash.filesystem.*;
        private var stream:FileStream;
        private function saveFile():void{
            var file:File = File.desktopDirectory.resolvePath("HelloWorld.txt");
            var stream:FileStream = new FileStream()
            stream.open(file, FileMode.WRITE);
            var str:String = "Congratulations on your 1st file, Rich Tretola - EverythingFlex.com";
            stream.writeUTFBytes(str);
            stream.close();
            mx.controls.Alert.show("File has been saved to \n" + file.nativePath, "Notice");
        }
    ]]>
    </mx:Script>
    <mx:Button label="Create File" click="saveFile()"
        horizontalCenter="0" verticalCenter="0" />
</mx:WindowedApplication>