Jumping Spiders don't build webs to catch prey, but instead chase bugs down and jump on them! They can literally snatch a fly out of mid air. There are over 5000 species of jumping spider, this LOOKs like it may be Phidippus Audax (Bold Jumpers). But I wouldn't stake my life on it. Spider experts say that to properly identify a spider they frequently have to put it under a microscope.
This fat little spider was very shy, which is unusual for Salties. But I finally managed to get it to pose for me.