Jumping
spiders are members of the family
Salticidae. They have the best
eyesight of all spiders, with four big
eyes on the front of their head that make them look almost like a
Toyota Land Cruiser. The other four eyes are smaller and are on the back of their head. Their excellent eyesight is used to
stalk their
prey, spotting unsuspecting
insects from up to a couple of feet away, then
pouncing on them like a
cat.
If you see a spider that has noticed you and is turning its head to watch you, it is probably a jumping spider.
Since jumping spiders catch their prey by hunting, they don't need webs to do that job. The webs they build are instead used for shelter, and are often a crude lean-to placed in a crack of a building.
Salticids have interesting and elaborate courtship dances, in which the male raises his front legs and waves them in precise ways to attract females. This sort of courtship display wouldn't work in species with poor vision.