How to put a animation in background in a html page

Answer 1

What exactly are you aiming to do? Perhaps this may give you an idea https://davidwalsh.name/background-animation-css

Answer 2

gif file

Answer 3

We must know more accuratly what kind of animation you want to do at your background: there are many technologies to do them, so some are more adapted to certain cases, while other for other purposes ;)

Answer 4

no gif file @jason