IMMEDIATE: FROTHING MOUTH AND SEIZURE IN MY DOG

My dog abruptly started showing signs of a serious seizure. He's having froth coming from his mouth and can't stand up. I don't know what to try. Please help! Is this a sign of something really bad? I'm so scared, he's my best friend. My Dog Is Having a Seizure, Foaming at the Mouth It's incredibly frightening to witness your dog/your pet/my fu