Passing Variable to ActionScript

I have been looking for this couple hours and still can’t find the answer. I need to pass variable BUT only through URL as I need to use it as a target link in html (so I can’t use <object> flashvars), look below.

<a href=“www.site.com/[COLOR=Red]flash.swf?choice=1[/COLOR]”>link</a>

My question is if I use link like the one above how do I read the variable choice in actionscript, I have my code in the main document file as.

Dave