|MadSci Network: Zoology|
The spider you saw probably was a jumping spider (family Salticidae). These are not generally considered to be dangerous, although there have been some reports of a mild reaction to their bites. They are not aggressive and you would have to try and grab one or get it crushed between clothing and skin to get bitten. They build resting or molting sacs in which they molt their "skin" or in which females may lay eggs. They do not build capture webs. Actually, most of the spiders considered to be dangerous that are found in this country have thin legs. The black widow and the brown recluse and the related violin spiders are rather spindly- legged spiders. Most "short-legged" spiders are not dangerous, but as we know little about some spider's venoms it is wise to avoid handling them.
Try the links in the MadSci Library for more information on Zoology.