When your dog has a seizure they might start jerking, twitching, drooling, chewing on there tongue, foam at the mouth and your dog might also fall to the side and start moving their legs in a paddling motion.
If your dog starts having seizures you should take them to the vet so they can help the dog with the seizures.
If you start noticing any of those symptoms contact your vet as soon as possible and have the dog checked out.