Affiliate Marketing Secrets

Hi, I need to pass an affiliate ID string from one html file to another for as long as the user is browsing my site.
Can someone please explain to me how to do this using a simple java script function (no php or asp).
In my command line I would put something like: mypage.html?affiliateid=1234
How would I retrieve this parameter and then put it in every link on my page so that it is passed on to any page the user surfs to?
Any help would be greatly appreciated.