php几个预定义变量$_SERVER['DOCUMENT_ROOT']

<?php

echo 'documentroot:'.$_SERVER['DOCUMENT_ROOT'].'<br>'; //根目录,在apache的配置文件里定义：httpd.conf 比如：DocumentRoot "D:/work/php_root"
echo 'httphost:'.$_SERVER['HTTP_HOST'].'<br>';　//域名，比如：localhost
echo 'phpself:'.$_SERVER['PHP_SELF'].'<br>';   // 从根目录到文件本身的路径
echo 'script filename'.$_SERVER['SCRIPT_FILENAME'].'<br>';　／／documentroot+phpself
echo 'request uri'.$_SERVER['REQUEST_URI'].'<br>';　//从根目录开始所有的ＵＲＬ字符串，包括问号之后的字符
echo 'request method:'.$_SERVER['REQUEST_METHOD'].'<br>';　／／请求的方法
echo 'name:'.$_REQUEST['name'].'<br>';　／／请求参数的值

?>

IE type in:http://localhost/shong/test2/test1.php?name=shong

documentroot:D:/work/php_root
httphost:localhost
phpself:/shong/test2/test1.php
script filenameD:/work/php_root/shong/test2/test1.php
request uri/shong/test2/test1.php?name=shong
request method:GET
name:shong