网页判断浏览器是否安装flash

<script>
//检验flash版本 以及falsh是否安装
    function detectFlash() {
        try {
            if(navigator.mimeTypes.length>0) {
                var flashAct = navigator.mimeTypes["application/x-shockwave-flash"];
                var desc = flashAct.enabledPlugin.description;
                var version = parseInt(desc.substr(desc.toLowerCase().lastIndexOf("flash ") + 6));

                return version > 10;
            } else {
                var act = new ActiveXObject(‘ShockwaveFlash.ShockwaveFlash‘);
                var flashVersion = act.GetVariable("$version");
                flashVersion = flashVersion.replace(/^.*?([0-9]+).*$/, ‘$1‘);

                return flashVersion > 10;
            }
        } catch (oError) {
            return false;
        }
        return false;
    }
	
	alert(detectFlash())
</script>