<?php
$UserAgent = $_SERVER['HTTP_USER_AGENT'];

if(isset($_SERVER['HTTP_X_FORWARDED_FOR']) && $_SERVER['HTTP_X_FORWARDED_FOR']){
         // is a proxy so automatically don't show anything
         $IP = $_SERVER["HTTP_X_FORWARDED_FOR"];
         $proxy = $_SERVER["REMOTE_ADDR"];
    }else{
         // for normal user
         $IP = $_SERVER["REMOTE_ADDR"];
        //check if the IP is in your proxy/tor database or whatever and don't show the adsense javascript if it is
    }

?>