broken gas cap tab?

i went to get gas today at the store,the cap was hard to get off.
when i did the cap only has one tab on it,i though it use to have two,maybe the other one fell off in the tank.i could buy another cap at the auto store and use a magnet wand thingy to get the tab out. but does anybody know how many tabs is on there cap?

thanks for any help you can give,i'll look in the cap.

i switched to using a rubber oil plug for a cap,but it fell off and i lost it and had to use the origional gas cap with only one tab,now the second tab fell off.now i have tape holding my cap on. anyone have any ideas what to use for a cheap replacement cap?
anyone have any part numbers for a car gas cap that will fit?that way i wont have to pay high shipping prices and can buy it local.

i actually do have a part number for a rubber/plastic cap(non vented) from Napa.
its a oil filler cap and you can make a hole in center and put a tube for venting.
part# 703-2300
it fits the tank but mine flew off when i hit a bump but i may get another one and try it again since it doesnt leak. and it costs only $2-3

maybe this time i will add a strap on it so i dont loose it,lol.

i'll look in my cap and see what the tab looks like, cause i here it rattleing around in there. but i'll be suprized if its one piece cause it looked like a single hinged tab on each side of cap,but if its one piece i might be able to fix it.

UPDATE: i took the cap off and looked at it,somethings rattleing in there.
so i had to figure how to take the cap apart, tryed to take top of cap apart,didnt work,so i made a hole in the bottom of cap where the small holes are,left flaps of metal so i could close it back up and hold the spring in there. i found the tab ( its a one piece metal tab) wow,cool. Everyone becareful cause its a springloaded spring in there(where eye pertection). so i fixed the tab after a couple of hours of playing with spring and tab and closed the tabs of metal at bottom of cap,that will hold the spring in there.and guess what ,the top of the cap finally fell off,so i had to pop it back on there,if it would have came off earlier i wouldnt of had to cut the bottom of the cap,o well its fixed for now and seals better and tighter than ever and with a twist its easy to take off too,its better than new,lol and i saved some money,but i still reccomend anyone else just to go buy another cap,but that one could break too,lol. Thanks for everyones help, especially just gassit who said it was a one piece tab and got me to go look in the cap.

I fixed my gas cap and its better than new.