怎样样能够获取服务器和浏览器变量?

怎样样能够获取服务器和浏览器变量?

<html>

<head>

<title>
服务器和浏览器变量获取示例
</title>

</head>

<meta http-equiv=content-type content="text/html; charset=gb2312">

<body>

<?
echo "<h2 align=center >服务器和浏览器的信息</h2>/n";

echo "<hr color=red>";
echo "<p>";
echo "<table align=center width=80% border=1>/n";

echo "<tr><td>REMOTE_HOST</td><td>$REMOTE_HOST</td></tr>/n";
echo "<tr><td>SERVER_SOFTWARE </td><td> $SERVER_SOFTWARE</td></tr>/n";
echo "<tr><td>DOCUMENT_ROOT </td><td> $DOCUMENT_ROOT</td></tr>/n";
echo "<tr><td>REMOTE_ADDR </td><td> $REMOTE_ADDR</td></tr>/n";
echo "<tr><td>SERVER_PROTOCOL </td><td> $SERVER_PROTOCOL</td></tr>/n";
echo "<tr><td>REQUEST_METHOD </td><td> $REQUEST_METHOD</td></tr>/n";
echo "<tr><td>HTTP_USER_AGENT </td><td> $HTTP_USER_AGENT</td></tr>/n";

echo "</table>/n"

?>

</body>

</html>