1 <!--PHP的环境变量 --> 2 <?php 3 echo "环境变量\n"; 4 echo "浏览器的版本:"."$_SERVER['HTTP_USER_AGENT']"."\n"; 5 echo "客户端的IP地址:".$_SERVER['REMOTE_ADDR']."\n"; 6 echo "网站的主机名:".$SERVER['HTTP_HOST']."\n"; 7 echo "客户端的端口:".$SERVER['REMOTE_PORT']."\n"; 8 echo "网站所有的目录:".$SERVER['DOCUMENT_ROOT']."\n"; 9 echo "服务器的操作系统:".$SERVER['OS']."\n"; 10 echo "服务器的系统路径:".$SERVER['PATH']."\n"; 11 ?> 12 <!--PHP的系统常量 --> 13 <?php 14 echo "当前服务器操作系统:".PHP_OS."\n"; 15 echo "当前PHP的版本:".PHP_VERSION."\n"; 16 echo "当前的行号:"._LINE_."\n"; 17 echo "当前的PHP文件:"._FILE_."\n\n"; 18 $s=2; 19 echo "圆的半径:".$s."\n"; 20 echo "圆的周长:".M_PI*2*$s."\n"; 21 ?>