前辈JS navigator.appName 不同浏览器 屏幕输出均为“Netscape”?

 <body>
    <div id="example"></div>
    <script>
        var txt="<p>Browser Name:"+navigator.appName||window.opera+"</p>"
        //var txt="<p>Browser Name:"+window.opera+</p>"
        txt+="<p>Browser Version:"+navigator.appVersion+"</p>"
        txt+="<p>Cookies Enabled:"+navigator.cookieEnabled+"</p>"
        txt+="<p>Platform:"+navigator.platform+"</p>"

        document.getElementById("example").innerHTML=txt;
    </script>

</body>