If your dog had a seizure, especially one that lasted 5 - 10 minutes, then you he needs to go see a vet immediately. I'm unsure of why this post is even on here when there are emergency pet clinics everywhere these days that should be called while this is happening. Think of a couple things, as well:
Did he eat something like prescription meds, chemical cleaners or weird plants outside?
What is his behavior like?
Are there toads in the area? (Granted, this wasn't a toad toxicity, as your dog is still alive)
Seizures can be treated very easily and without a great expense to you, so get off your butt and hit the vet up. It's not fair to your dog if you decided to ignore the problem until it becomes impossible to treat.