<?
//本例用PHP4实现顶级域名查询
if ($domain)
{
if ($domain)
{
//连接到internic域名服务器
$fp = fsockopen( "rs.internic.net", 43, &$errno, &$errstr, 10);
if (!$fp)
{
echo "$errstr ($errno)<br>\n";
}
else
{
fputs($fp, "$domain\r\n");
while(!feof($fp))
{
$buf = fgets($fp,128);
if (ereg( "Whois Server:", $buf))
{
$server = str_replace( "Whois Server: ", "", $buf);
$server = trim($server);
}
}
fclose($fp);
}
if ($server)
{
echo "<B>$domain 的注册服务器是 $server:</B><BR>";
echo "<PRE>";
$fp = fsockopen($server, 43, &$errno, &$errstr, 10);
if(!$fp)
{
echo "不能连接到服务器 $server 的43端口.\n";
echo "$errstr ($errno)<br>\n";
}
else
{
fputs($fp, "$domain\r\n");
while(!feof($fp))
{
echo fgets($fp,128);
}
fclose($fp);
}
}
else {
echo( "<b>$domain 没有注册。</b><BR>");
}
echo ( "</PRE><BR>");
}

}
?>

<FORM ACTION=" <?PHP echo($PHP_SELF); ?>" METHOD="post">
只能查询.com,.net和.org的域名<br>
输入域名：<INPUT TYPE="text" NAME="domain" SIZE="30" MAXLENGTH="100">
<INPUT TYPE=submit VALUE="查 询">
</FORM>
上面例子中运行又错误，不知为什么？我刚学的，请大家多多教导！if($domain)这里又是错误