I did like you said but it shows this right now:
Notice: Use of undefined constant maxQuantity - assumed 'maxQuantity' in C:\xampp\htdocs\BYZANTINO_BOSTON\WA_eCart\eCart_BYZANTINO_PHP.php on line 12
here is line 12:
$itmObj->QuantityAvailable = abs($itmObj->Quantity > [maxQuantity])?$itmObj->Quantity = [maxQuantity]:0;//t