why is my gs3 acting weird

A

AC Question

My gs3 turns off all the time ....Well it don't turn on only when I use my charger.It was working just fine this morning then it started acting all weird and then just shut offed.So now I need to leave it on the charger and as soon as I unplug it powers off..
Anyone know what is happing.....please need some answers A.S.A.P