My ipad won't charge

I've been trying to charge my ipad but there is no indication that its charging. (No lightning bolt sign) when I put my charger in the percentage sign (next to the battery icon on the top right of the ipad) will go down it was at 80 percent when I began this afternoon and now it's at 19 percent and my charge was in my ipad the whole time. PLEASE HELP!!!!!!!!!!!!!