js:

    <script>
            function setDate(){
                 var flash = (navigator.appName.indexOf ("Microsoft") !=-1)?window["test"]:document["test"];
                 flash.yun("good");
            }

    </script>

    <object width="400" height="24"  classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000">
            <param name="movie" value="test.swf">
            <embed src="test.swf" width="400" height="24"></embed>
    </object> 
    <button onclick="setDate()">test</button>

as:

    public function test() {
            if (ExternalInterface.available) {
                try {
                    ExternalInterface.addCallback("yun",yun);
                }catch(error:SecurityError){
                    yun("SecurityError");
                }catch(error:Error){
                    yun("Error");
                }
            }else{
                yun("available false");
            }

        }
        public function yun(zi:String):void{
            var mtext:TextField = new TextField();
            mtext.text = zi;
            addChild(mtext);
        }

另外问下flash参数里的window[test]的这个test究竟是swf名字，还是object的id，还是其他，真没搞懂