Formal exceptions to rulings or orders of the court are unnecessary; but for all purposes for which an exception has heretofore been necessary it is sufficient that a party, at the time the ruling or order of the court is made or sought, makes known to the court the action which he desires the court to take or his objection to the action of the court and his grounds therefor except it shall not be necessary to state grounds for objections for instructions; and, if a party has no opportunity to object to a ruling or order at the time it is made, the absence of an objection does not thereafter prejudice him.