document.write('Ваш IP - xxx.x.xxx.xxx
');

<?php
$ip = return_IP();
echo "document.write('Ваш IP - ".$ip."<BR>');";
function return_IP()
{
$first = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR']:Null;
$second = isset($_SERVER['HTTP_X_FORWARDED_FOR']) ? $_SERVER['HTTP_X_FORWARDED_FOR']:NULL;
$third = isset($_SERVER['HTTP_PROXY_USER']) ? $_SERVER['HTTP_PROXY_USER']:NULL;
$array = array(1 => $first,2 => $second,3 => $third );

if ( !is_array($array) ) return -1;
$chosen = -1;
foreach ($array as $k => $v) {
if (isset($v)) {
$chosen = $v;
break;
}
}
return $chosen;
}
?>