What kind of spider is black hairy thin and has white spots on its back?

It sounds like the harmless "Daring jumping spider," Phidippus audax, which is commonly found all over the United States. This small spider is black and furry with a couple white spots on its back. Four of it's anterior eyes are very large and you should be able to see them without a magnifying glass. The spider also has emerald green pedipalps. Without a location it's very hard to tell exactly what it could be. If the spider is not furry at all, I suggest staying away from it if you live in a tropical area as it could be poisonous.