a easy quick search got this......does anyone look for things themselves anymore??? http://www.sweetwater.com/shop/bass-...ying-guide.php
So how do they differ? What makes a player choose one over the other? The primary differences can be summed up in three areas: the body, the neck and the pickups.
If I said you have a beautiful body...
The Precision Bass looked radical in 1951. Its deep double cutaways and forward-raked design was like nothing the guitar world had seen. And it preceded the Stratocaster (which has a similar body style) by three years. In 1954 the Precision Bass, which had been a "slab" until then, adopted the contoured body of the new Stratocaster. These sculpted recessions at the bottom and top made it more comfortable to hold. The original Precision body was ash; now you can choose from models with ash or alder bodies.
The Fender Jazz Bass, released in 1960, offered players an alternative to the Precision. Its offset-waist body, which was drawn from the Jazzmaster guitar introduced a couple of years earlier, moved the mass of the body forward and out of the way of the player's right arm. As with the P Bass, ash and alder body models of the J Bass are available.
Neck and neck...
Most Precision and Jazz Bass production models have what Fender calls a "modern C shape" neck. Each model's neck is maple, with maple, rosewood, or pao ferro fingerboards available. But there the similarities end. Each neck is distinctively different to appeal to different players' preferences. The Precision neck maintains a fairly consistent thickness and tapers in slightly as it approaches the nut.
Meanwhile, the Jazz starts with its strings in a noticeably narrower spacing at the nut that give it a distinct "tapered" feel for what some players feel is easier fingering. And the fast-action maple Jazz neck debuted with a rosewood fingerboard that made it easier to manage.
With that in mind, though, a wide variety of neck options are open to today's P Bass or J Bass buyers. From Custom Shop models with a full "C" shape to Artist Series Jazz with Precision necks and Precisions with Jazz necks (as with the Deluxe Series P Bass Special), you can have the body/neck combination that suits you best.
A couple of pickup lines...
Upon its first release the Precision Bass had a single-coil pickup with a chrome-plated cover. Within a few years Fender moved to a split-coil pickup that offered a more defined and solid bass sound.
The Jazz came out of the chute with dual eight-pole humbucking pickups that gave players a wider variety of tonal possibilities, thanks in part to a softer, less spiky signal that was not possible with the P Bass's single-coil pickup. The end result was a bass some players consider to have a cleaner sound, with more tonal variation possible through use of a pan knob that adjusts the balance between the two pickups.