Random header using css and javascript?

well the title pretty much explains what i am trying to do… but i’ll explain. i am making a site using an external css file to control everything. what i would like to do is have a random header on each page (because i can’t use php). is there anyway that i can do this from the external css file so that i don’t have to update each page if/when i make new headers?

hope that makes sense. let me know.
thanks