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                        /JavaScript进阶篇

请问为什么"当前URL的端口号为："和"当前从问号(?)开始的URL(查询部分)为："没有输出

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>location</title>
</head>
 <script type="text/javascript">
        var myhash=window.location.hash;
        var myhost=window.location.host;
        var myhostname=window.location.hostname;
        var myhref=window.location.href;
        var mypathname=window.location.pathname;
        var myport=window.location.port;
        var myprotocol=window.location.protocol;
        var mysearch=window.location.search;
        
        document.write("当前从#开始的URL值为:"+myhash+"<br />");
        document.write("当前主机名和当前URL的端口号为:"+myhost+"<br />");
        document.write("当前URL的主机名为:"+myhostname+"<br />");
        document.write("当前完整的URL为："+myhref+"<br />");
        document.write("当前URL的路径部分为："+mypathname+"<br />");
        document.write("当前URL的端口号为："+myport+"<br />");
        document.write("当前URL的协议为："+myprotocol+"<br />");
        document.write("当前从问号(?)开始的URL(查询部分)为："+mysearch);
 </script><body></body></html>