How do I access a variable in my html / swf parameters?

So I’m trying to do something like this…

<param name=“movie” value=“comp.swf?rootDomain=3” />

where I have a variable called ‘rootDomain’ in my html, as a parameter.

I want to be able to call that from my flash, but whenever I try it comes up as undefined.

I’m using this code in my flash…

on(release){getURL (_root.rootDomain + ‘/news/’), “_self”

}

I don’t know if I’m just wrong, if it’s syntax or what, but how do I reference that variable in the html with my code?

Thanks.