PHP - 等于不等于但应该是

Have a bit of a problem with some current code we're using Android to POST to PHP where using the following code

$fbid = $_POST['fbid'];

if($fbid == "no"){
echo 'no fbid';
}else{
echo 'fbid look for user';
}

We used the following strlen($fbid) which returns 2

All the posted strings don't seem to match and when used strlen() on all equal the correct amount - any ideas? could this be encoding problem?

Just as a trivial suggestion:

if($fbid == "no"){
    echo 'no fbid';
}else{
    echo 'fbid look for user';
}