[AS3]as3生成随机验证码源代码（包含数字和字母）

<?xml version="1.0" encoding="utf-8"?> 
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
               xmlns:s="library://ns.adobe.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx" 
               creationComplete="init(event)"> 
    <fx:Script> 
        <![CDATA[ 
            import mx.events.FlexEvent; 
            protected function init(event:FlexEvent):void 
            { 
                checkCode.text=GenerateCheckCode(); 
            } 
              
            //生成随机码 
            private function GenerateCheckCode():String 
            { 
                //初始化 
                var ran:Number; 
                var number:Number; 
                var  code:String; 
                var checkCode:String =""; 
                //生成四位随机数 
                for(var i:int=0; i<4; i++) 
                { 
                    //Math.random生成数为类似为0.1234 
                    ran=Math.random(); 
                    number =Math.round(ran*10000); 
                    //如果是2的倍数生成一个数字 
                    if(number % 2 == 0) 
                        //"0"的ASCII码是48  
                        code = String.fromCharCode(48+(number % 10)); 
                        //生成一个字母 
                    else  
                        //"A"的ASCII码为65 
                        code = String.fromCharCode(65+(number % 26)) ; 
                    checkCode += code; 
                } 
                return checkCode; 
            } 
        ]]> 
    </fx:Script> 
    <s:Label x="10" y="10" id="checkCode" color="#377CD0" click="checkCode.text=GenerateCheckCode();" /> 
</s:Application>