Can anyone help me identify this jellyfish?

Will on vacation in Florida this last weekend, my mother saw a very blue jellyfish that looked almost like it was made of plastic. I thought it might be something dangerous, like a man o’ war, but there were a couple strewn all over the beach, and it wasn’t closed. She snapped a picture of one with her cell phone (that’s why the quallity is so horrible).

Maybe a jelly can identify a jelly?