Getting visitors country from their IP using PHP

<?php
function getRealIpAddr()
{
    if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet
    {
      $ip=$_SERVER['HTTP_CLIENT_IP'];
    }
    elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))   //to check ip is pass from proxy
    {
      $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
    }
    else
    {
      $ip=$_SERVER['REMOTE_ADDR'];
     // $ip="5.2.79.255";//Netherland
     // $ip="81.247.97.77";//Belgium
    }
    return $ip;
}

$xml = simplexml_load_file("http://www.geoplugin.net/xml.gp?ip=".getRealIpAddr());
echo $xml->geoplugin_countryName ;

echo "<pre>" ;
foreach ($xml as $key => $value)
{
    echo $key , "= " , $value ,  " \n" ;
}
?>