<?php    
//首先确保 $_SERVER['DOCUMENT_ROOT'] 变量设置了 
if(!isset($_SERVER['DOCUMENT_ROOT'])) 
{    
  if(isset($_SERVER['SCRIPT_FILENAME'])) 
  { 
  $_SERVER['DOCUMENT_ROOT'] = str_replace( '\\', '/', substr($_SERVER['SCRIPT_FILENAME'], 0, 0-strlen($_SERVER['PHP_SELF']))); 
  } 
} 
if(!isset($_SERVER['DOCUMENT_ROOT'])) 
{ 
  if(isset($_SERVER['PATH_TRANSLATED'])) 
  { 
  $_SERVER['DOCUMENT_ROOT'] = str_replace( '\\', '/', substr(str_replace('\\\\', '\\', $_SERVER['PATH_TRANSLATED']), 0, 0-strlen($_SERVER['PHP_SELF']))); 
  } 
} 
//现在可以使用$_SERVER['DOCUMENT_ROOT']了... 
 
echo $_SERVER['DOCUMENT_ROOT']; 

 ?>

本文转自 xcf007 51CTO博客，原文链接：http://blog.51cto.com/xcf007/111058，如需转载请自行联系原作者