To Show IP Address via PHP 

 <?
$remote_address = getenv("REMOTE_ADDR");
echo "Your IP address is $remote_address.";
$browser_type = getenv("HTTP_USER_AGENT");
echo "You are using $browser_type.";
?>

To show the IP Address via JavaScript 

 var ip= '<!--#echo var="REMOTE_ADDR"-->';
document.write("Your IP Address is :"+ip+" ");