sudden laughter

Hi mommies. So recently, my 2 yo boy started his random laughing for no apparent reason.. he'd either laughs after a blank stare or when he's looking outside the car window or house gate... Is it possible for a 2yo to hv just had a funny thought and laugh at it, or should i get him checked? P.s: i recently gave him an ipad for games and youtube, but only few hours daily. Could this be the cause?