Parked car at store, came back and it wouldn't start.

There was a lot of fluid on the parking lot under the car. It is brownish and slippery. It looks like it came from the middle to back of the car on the passenger side. Very hot day and I had the AC on high when I started the car. Don't know if this matters or not.

The car will not start, but will turn over and the power windows and radio work, so it doesn't sound like the battery. The car is the the grocery parking lot, since its the weekend and auto repair shop is closed. thank you for any help you can give.