#after reading in the values
if($username eq "" || $hashPassword == $null) {

        
        error();

}else{
#after comparing them to the actual passwords stored in
$sth = $db->prepare(q{SELECT userid, password from user where userid = ?})
        or die("usr prepare error: $!");
$usr->execute($username)
        or die("usr prepare error: $!");


   while(@row  = $sth->fetchrow_array){
        if($username eq $row[0] && $hashPassword eq $row[1])    {

               #Go to the new page
       }elsif($username ne $row[0] || $hashPassword != $row[1]) {

                  error();

       }elsif($username eq $row[0] && $hashPassword != $row[1]) {

                  error();

       }elsif($username ne $row[0] && $hashPassword == $row[1]) {

                 error();

       }elsif($username ne $row[0] && $hashPassword != $row[1]) {

                 error();

}
}