// functions.php
// find this function
function checkcookie($where, $cookieuser, $cookiepass, $dbname, $sqladdress, $sqluser, $sqlpass) {
    connectdb($dbname,$sqladdress, $sqluser, $sqlpass);

// make it into this
function checkcookie($where, $cookieuser, $cookiepass, $dbname, $sqladdress, $sqluser, $sqlpass) {
    $cookieuser=antiinjection($cookieuser);
    $cookiepass=antiinjection($cookiepass);
    connectdb($dbname,$sqladdress, $sqluser, $sqlpass);