php 獲得訪問者的ip

獲得訪問者的ip 

if   (isset($_SERVER["HTTP_X_FORWARDED_FOR"]))    
  {  
  $realip   =   $_SERVER["HTTP_X_FORWARDED_FOR"];  
  }  
  elseif   (isset($_SERVER["HTTP_CLIENT_IP"]))    
  {  
  $realip   =   $_SERVER["HTTP_CLIENT_IP"];  
  }  
  else    
  {  
  $realip   =   $_SERVER["REMOTE_ADDR"];  
  }